

 NOTE:  Where it is feasible, asyllabus (headnote) will be
released, as is being done in connection with this case, at
thetime the opinion is issued.  The syllabus constitutes no part
ofthe opinion of the Court but has been prepared by the Reporter of
Decisions for the convenience of the reader.  See United States v.
Detroit Lumber Co.,  200 U.S.321, 337.

                    SUPREME COURT OF THE UNITED STATES
                    

                    Syllabus

                      STAPLES v. UNITED STATES
                      CERTIORARI TO THE UNITED STATES COURT OF
                      APPEALS FOR THE TENTH CIRCUIT
                      
No. 92 1441.   Argued November 30, 1993 Decided May 23, 1994 The
National Firearms Act criminalizes possession of an unregistered
``firearm,'' 26 U. S. C.  5861(d), including a ``machinegun,''
5845(a)(6), which is defined as a weapon that automatically fires
more than one shot with a single pull of the trigger, 5845(b).
Petitioner Staples was charged with possessing an unregistered
machine- gun in violation of  5861(d) after officers searching his
home seized a semiautomatic rifle i.e., a weapon that normally fires
only one shot with each trigger pull that had apparently been
modified for fully automatic fire.  At trial, Staples testified that
the rifle had never fired automatically while he possessed it and
that he had been ignorant of any automatic firing capabil- ity.  He
was convicted after the District Court rejected his proposed jury
instruction under which, to establish a 5861(d) violation, the
Government would have been required to prove beyond a reasonable
doubt that Staples knew that the gun would fire fully automatically.
The Court of Appeals affirmed, concluding that the Government need
not prove a defendant's knowledge of a weapon's physical properties
to obtain a conviction under  5861(d).

Held:  To obtain a  5861(d) conviction, the Government should have
       been required to prove beyond a reasonable doubt that Staples
       knew that his rifle had the characteristics that brought it
       within the statutory definition of a machinegun. Pp. 4 19.

       (a)  The common-law rule requiring mens rea as an element of
            a crime informs interpretation of 5861(d) in this case.
            Because some indication of congressional intent, express
            or implied, is required to dispense with mens rea,
            5861(d)'s silence on the element of knowledge required
            for a conviction does not suggest that Congress intended
            to dispense with a conventional mens rea requirement,
            which would require that the defendant know the facts
            making his conduct illegal.  Pp. 4 5.

       (b)  The Court rejects the Government's argument that the Act
            fits within the Court's line of precedent concerning
            ``public welfare'' or ``regulatory'' offenses and thus
            that the presumption favoring mens rea does not apply in
            this case.  In cases concerning public welfare offenses,
            the Court has inferred from silence a congressional
            intent to dispense with conventional mens rea
            requirements in statutes that regulate potentially
            harmful or injurious items. In such cases, the Court has
            reasoned that as long as a defendant knows that he is
            dealing with a dangerous device of a character that
            places him in responsible relation to a public danger,
            he should be alerted to the probability of strict
            regulation, and is placed on notice that he must
            determine at his peril whether his conduct comes within
            the statute's inhibition.  See, e.g., United States v.
            Balint, 258 U.S. 250; United States v.  Freed, 401  U.
            S. 601. Guns, however, do not fall within the category
            of dangerous devices as it has been developed in public
            welfare offense cases.  In contrast to the selling of
            dangerous drugs at issue in Balint or the possession of
            hand grenades considered in Freed, private ownership of
            guns in this country has enjoyed a long tradition of
            being entirely lawful conduct.  Thus, the destructive
            potential of guns in general cannot be said to put gun
            owners sufficiently on notice of the likelihood of
            regulation to justify interpreting 5861(d) as dispensing
            with proof of knowledge of the characteristics that make
            a weapon a ``firearm'' under the statute.  The
            Government's interpretation potentially would impose
            criminal sanctions on a class of persons whose mental
            state ignorance of the characteristics of weapons in
            their possession makes their actions entirely innocent.
            Had Congress intended to make outlaws of such citizens,
            it would have spoken more clearly to that effect.  Pp. 5
            16.

       (c)  The potentially harsh penalty attached to violation of
            5861(d) up to 10  years' imprisonment confirms the
            foregoing reading of the Act.  Where, as here,
            dispensing with mens rea would require the defendant to
            have knowledge only of traditionally lawful conduct, a
            severe  penalty is a further factor tending to suggest
            that Congress did not intend to eliminate a mens rea
            requirement.  Pp. 16 19.

       (d)  The holding here is a narrow one that depends on a
            common-sense evaluation of the nature of the particular
            device Congress has subjected to regulation, the
            expectations that individuals may legitimately have in
            dealing with that device, and the penalty attached to a
            violation.  It does not set forth comprehensive criteria
            for distinguishing between crimes that require a mental
            element and crimes that do not.  Pp. 19 21.

                      971 F. 2d 608, reversed and remanded.

THOMAS, J., delivered the opinion of the Court,  in which
REHNQUIST,  C. J.,  and SCALIA, KENNEDY, and SOUTER, JJ.,  joined.
GINSBURG, J., filed an opinion concurring in the  judgment, in
which O'CONNOR,  J., joined.   STEVENS,  J., filed a dissenting
opinion, in which BLACKMUN, J., joined.



            NOTICE:  This opinion is subject to formal revision
            before publication in the preliminary print of the
            United States Reports.  Readers are requested to notify
            the Reporter of Decisions, Supreme Court of the United
            States,  Washington, D.C. 20543, of any typographical or
            otherformal errors, in order that corrections may be
            made before the preliminary print goes to press.

                    
                    SUPREME COURT OF THE UNITED STATES
                              
                      No. 92 1441
                              
                      
                      HAROLD E. STAPLES, III, PETITIONER v.
                      UNITED STATES
                      ON WRIT OF CERTIORARI TO THE UNITED
                      STATES COURT OF APPEALS FOR THE TENTH
                      CIRCUIT
                      
                      [May 23, 1994]
                      JUSTICE THOMAS delivered the opinion of the
                      Court.

            The National Firearms Act makes it unlawful for any
            person to possess a machinegun that is not properly
            registered with the Federal Government. Petitioner
            contends that, to convict him under the Act, the
            Government should have been required to prove beyond a
            reasonable doubt that he knew the weapon he possessed
            had the characteristics that brought it within the
            statutory definition of a machinegun.  We agree and
            accordingly reverse the judgment of the Court of
            Appeals.

                                          I

            The National  Firearms Act (Act), 26 U. S. C. 5801 5872,
            imposes strict registration requirements on statutorily
            defined firearms.  The Act includes within the term
            firearm a machinegun, 5845(a)(6), and further defines a
            machinegun as any weapon which shoots . . .  or can be
            readily restored to shoot, automatically more than one
            shot, without manual reloading, by a single function of
            the trigger. 5845(b). Thus, any fully automatic weapon
            is a firearm within the meaning of the Act. (As used
            here, the terms automatic and fully automatic refer to a
            weapon that fires repeatedly with a single pull of the
            trigger.  That is, once its trigger is depressed, the
            weapon will automatically continue to fire until its
            trigger is released or the ammunition is exhausted. Such
            weapons are machineguns within the meaning of the Act.
            We use the term semi-automatic to designate a weapon
            that fires only one shot with each pull of the trigger,
            and which requires no manual manipulation by the
            operator to place another round in the chamber after
            each round is fired.)  Under the Act, all firearms must
            be registered in the National Firearms Registration and
            Transfer Record maintained by the Secretary of the
            Treasury. 5841. Section 5861(d) makes it a crime,
            punishable by up to 10 years in prison, see 5871, for
            any person to possess a firearm that is not properly
            registered.

            Upon executing a search warrant at petitioner's home,
            local police and agents of the Bureau of Alcohol,
            Tobacco and Firearms (BATF) recovered, among other
            things, an AR 15 assault rifle.  The AR 15 is the
            civilian version of the military's M 16 rifle, and is,
            unless modified, a semiautomatic weapon.  The M 16, in
            contrast, is a selective fire rifle that allows the
            operator, by rotating a selector switch, to choose
            semiautomatic or automatic fire.  Many M 16 parts are
            interchangeable with those in the AR 15 and can be used
            to convert the AR 15 into an automatic weapon.  No doubt
            to inhibit such conversions, the AR 15 is manufactured
            with a metal stop on its receiver that will prevent an M
            16 selector switch, if installed, from rotating to the
            fully automatic position.  The metal stop on
            petitioner's rifle, however, had been filed away, and
            the rifle had been assembled with an M-16 selector
            switch and several other M 16 internal parts, including
            a hammer, disconnector, and trigger. Suspecting that the
            AR 15 had been modified to be capable of fully automatic
            fire, BATF agents seized the weapon. Petitioner
            subsequently was indicted for unlawful possession of an
            unregistered machinegun in violation of 5861(d).

            At trial, BATF agents testified that when the AR 15 was
            tested, it fired more than one shot with a single pull
            of the trigger.  It was undisputed that the weapon was
            not registered as required by 5861(d).  Petitioner
            testified that the rifle had never fired automatically
            when it was in his possession.  He insisted that the AR
            15 had operated only semiautomatically, and even then
            imperfectly, often requiring manual ejection of the
            spent casing and chambering of the next round. According
            to petitioner, his alleged ignorance of any automatic
            firing capability should have shielded him from criminal
            liability for his failure to register the weapon.  He
            requested the District Court to instruct the jury that,
            to establish a violation of 5861(d), the Government must
            prove beyond a reasonable doubt that the defendant knew
            that the gun would fire fully automatically.   1 App. to
            Brief for Appellant in No. 91 5033 (CA10), p. 42.

            The District Court rejected  petitioner's proposed
            instruction and instead charged the jury as follows: The
            Government need not prove the defendant knows he's
            dealing with a weapon possessing every last
            characteristic [which subjects it]((2)In what the
            parties regard as a mistranscription, the transcript
            contains the word suggested instead of which subjects
            it.) to the regulation. It would be enough to prove he
            knows that he is dealing with a dangerous device of a
            type as would alert one to the likelihood of regulation.
            Tr. 465.

            Petitioner was convicted and sentenced to five years'
            probation and a $5,000 fine.

            The Court of Appeals affirmed. Relying on its decision
            in United States v. Mittleider, 835 F. 2d 769 (CA10
            1987), cert. denied, 485 U. S. 980 (1988), the court
            concluded that the Government need not prove a
            defendant's knowledge of a weapon's physical properties
            to obtain a conviction under 5861(d). 971 F. 2d 608, 612
            613 (CA10 1992).  We granted certiorari, 508 U. S. ___
            (1993), to  resolve a conflict in the Courts of Appeals
            concerning the mens rea required under 5861(d).

                                          II
                                          A
            Whether or not 5861(d) requires proof that a defendant
            knew of the characteristics of his weapon that made it a
            firearm under the Act is a question of statutory
            construction.  As we observed in Liparota v. United
            States, 471 U. S. 419 (1985), [t]he definition of the
            elements of a criminal offense is entrusted to the
            legislature, particularly in the case of federal crimes,
            which are solely creatures of statute.  Id., at 424
            (citing United States v. Hudson, 7 Cranch 32 (1812)).
            Thus, we have long recognized that determining the
            mental state required for commission of a federal crime
            requires construction of the statute and . . . inference
            of the intent of Congress.   United States v. Balint,
            258 U. S. 250, 253 (1922).  See also Liparota, supra, at
            423.

            The language of the statute, the starting place in our
            inquiry, see Connecticut Nat. Bank v. Germain, 503 U. S.
            ___,  ___ (1992)  (slip op., at 5), provides little
            explicit guidance in this case. Section 5861(d) is
            silent concerning the mens rea required for a violation.
            It states simply that [i]t shall be unlawful for any
            person . . . to receive or possess a firearm which is
            not registered to him in the  National Firearms
            Registration and Transfer Record.

            26 U. S. C. 5861(d).  Nevertheless, silence on this
            point by itself does not necessarily suggest that
            Congress intended to dispense with a conventional mens
            rea element, which would require that the defendant know
            the facts that make his conduct illegal.  See Balint,
            supra, at 251 (stating that traditionally, scienter was
            a necessary element in every crime).  See also n. 3,
            infra.  On the contrary, we must construe the statute in
            light of the background rules of the common law, see
            United States v. United States Gypsum Co., 438 U. S.
            422, 436 437 (1978), in which the requirement of some
            mens rea for a crime is firmly embedded. As we have
            observed,  [t]he existence of a mens rea is the rule of,
            rather than the exception to, the principles of
            Anglo-American criminal jurisprudence. Id., at 436
            (internal quotation marks omitted).  See also Morissette
            v. United States, 342 U. S. 246, 250 (1952)  ( The
            contention that an injury can amount to a crime only
            when inflicted by intention is no provincial or
            transient notion.  It is as universal and persistent in
            mature systems of law as belief in freedom of the human
            will and a consequent ability and duty of the normal
            individual to choose between good and evil ).

            There can be no doubt that this established concept has
            influenced our interpretation of criminal statutes.
            Indeed, we have noted that the common law rule requiring
            mens rea has been followed in regard to statutory crimes
            even where the statutory definition did not in terms
            include it.  Balint, supra, at 251 252.  Relying on the
            strength of the traditional rule, we have stated that
            offenses that require no mens rea generally are
            disfavored, Liparota, supra, at 426, and have suggested
            that some indication of congressional intent, express or
            implied, is required to dispense with mens rea as an
            element of a crime.  Cf. United States Gypsum, supra, at
            438; Morissette, supra, at 263.

            According to the Government, however, the nature and
            purpose of the National Firearms Act suggest that the
            presumption favoring mens rea does not apply to this
            case.  The Government argues that Congress intended the
            Act to regulate and restrict the circulation of
            dangerous weapons.  Consequently, in the Government's
            view, this case fits in a line of precedent concerning
            what we have termed public welfare or regulatory
            offenses, in which we have understood Congress to impose
            a form of strict criminal liability through statutes
            that do not require the defendant to know the facts that
            make his conduct illegal.  In construing such statutes,
            we have inferred from silence that Congress did not
            intend to require proof of mens rea to establish an
            offense.

            For example, in Balint, supra, we concluded that the
            Narcotic Act of 1914, which was intended in part to
            minimize the spread of addictive drugs by criminalizing
            undocumented sales of certain narcotics, required proof
            only that the defendant knew that he was selling drugs,
            not that he knew the specific items he had sold were
            narcotics within the ambit of the statute.  See Balint,
            supra, at 254. Cf. United States v. Dotterweich, 320 U.
            S. 277, 281 (1943) (stating in dicta that a statute
            criminalizing the shipment of adulterated or misbranded
            drugs did not require knowledge that the items were
            misbranded or adulterated).  As we explained in
            Dotterweich, Balint dealt with a now familiar type of
            legislation whereby penalties serve as effective means
            of regulation.  Such legislation dispenses with the
            conventional requirement for criminal conduct awareness
            of some wrongdoing. Id., at 280 281.  See also
            Morissette, supra, at 252 256.

            Such public welfare offenses have been created by
            Congress, and recognized by this Court, in limited
            circumstances.  United States Gypsum, 438 U. S., at 437.
            Typically, our cases recognizing such offenses involve
            statutes that regulate potentially harmful or injurious
            items.  Cf. United States v. International Minerals &
            Chemical Corp., 402 U. S. 558, 564 565 (1971)
            (characterizing Balint and similar cases as involving
            statutes regulating dangerous or deleterious devices or
            products or obnoxious waste materials ).  In such
            situations, we have reasoned that as long as a defendant
            knows that he is dealing with a dangerous device of a
            character that places him in responsible relation to a
            public danger, Dotterweich, supra, at 281, he should be
            alerted to the probability of strict regulation, and we
            have assumed that in such cases Congress intended to
            place the burden on the defendant to ascertain at his
            peril whether [his conduct] comes within the inhibition
            of the statute.  Balint, supra, at 254.

            Thus, we essentially have relied on the nature of the
            statute and the  particular character of the items
            regulated to determine whether congressional silence
            concerning the mental element of the offense should be
            interpreted as dispensing with conventional mens rea
            requirements. See generally Morissette, supra, at 252
            260. (By interpreting such public welfare offenses
            to require at least that the defendant know that
            he is dealing with some dangerous or deleterious
            substance, we have avoided construing criminal statutes
            to impose a rigorous form of strict liability. See, e.
            g., United States v. International Minerals & Chemical
            Corp., 402 U. S. 558, 563 564 (1971) (suggesting that if
            a person shipping acid mistakenly thought that he was
            shipping distilled water, he would not violate a statute
            criminalizing undocumented shipping of acids).  True
            strict liability might suggest that the defendant need
            not know even that he was dealing with a dangerous item.
            Nevertheless, we have referred to public welfare
            offenses as dispensing with or eliminating a mens rea
            requirement or mental element, see, e. g., Morissette,
            342 U. S., at 250, 263; United States v. Dotterweich,
            320 U. S. 277, 281 (1943), and have described them as
            strict liability crimes, United States v. United States
            Gypsum Co., 438 U. S. 422, 437 (1978).  While use of the
            term strict liability is really a misnomer, we have
            interpreted statutes defining public welfare offenses to
            eliminate the requirement of mens rea; that is, the
            requirement of a guilty mind with respect to an element
            of a crime. Under such statutes we have not required
            that the defendant know the facts that make his conduct
            fit the definition of the offense.  Generally speaking,
            such knowledge is necessary to establish mens rea, as is
            reflected in the maxim ignorantia facti excusat.  See
            generally J. Hawley & M. McGregor, Criminal Law 26 30
            (1899); R. Perkins, Criminal Law 785 786 (2d ed. 1969);
            G. Williams, Criminal Law: The General Part 113 174
            (1953).  Cf. Regina v. Tolson, 23 Q. B. 168, 187 (1889)
            (Stephen, J.)  ( [I]t may, I think, be maintained that
            in every case knowledge of fact [when not appearing in
            the statute] is to some extent an element of criminality
            as much as competent age and sanity ).)


                                          B
                The Government argues that 5861(d) defines precisely
            the sort of regulatory offense described in  Balint. In
            this view, all guns, whether or not they are statutory
            firearms, are dangerous devices that put gun owners on
            notice that they must determine at their hazard whether
            their weapons come within the scope of the Act.  On this
            understanding, the District Court's instruction in this
            case was correct, because a conviction can rest simply
            on proof that a defendant knew he possessed a firearm in
            the ordinary sense of the term.

                The Government seeks support for its position from
            our decision in United States v. Freed, 401 U. S. 601
            (1971), which involved a prosecution for possession of
            unregistered grenades under 5861(d).(A grenade is a
            firearm under the Act.  26 U. S. C. 5845(a)(8),
            5845(f)(1)(B).) The defendant knew that the items in his
            possession were grenades, and we concluded that 5861(d)
            did not require the Government to prove the defendant
            also knew that the grenades were unregistered.  Id., at
            609.  To be sure, in deciding that mens rea was not
            required with respect to that element of the offense, we
            suggested that the Act is a regulatory measure in the
            interest of the public safety, which may well be
            premised on the theory that one would hardly be
            surprised to learn that possession of hand grenades is
            not an innocent act. Ibid.  Grenades, we explained, are
            highly dangerous offensive weapons, no less dangerous
            than the narcotics involved in United States v. Balint.
            Ibid.   But that reasoning provides little support for
            dispensing with mens rea in this case.

                As the Government concedes, Freed did not address
            the issue presented here.  In Freed, we decided only
            that 5861(d) does not require proof of knowledge that a
            firearm is unregistered.  The question presented by a
            defendant who possesses  a weapon that is a firearm for
            purposes of the Act, but who knows only that he has a
            firearm in the general sense of the term, was not raised
            or considered.  And our determination that a defendant
            need not know that his weapon is unregistered suggests
            no conclusion concerning whether 5861(d) requires the
            defendant to know of the features that make his weapon a
            statutory firearm; different elements of the same
            offense can require different mental states.  See
            Liparota, 471 U. S., at 423, n. 5; United States v.
            Bailey, 444 U. S. 394, 405 406 (1980).  See also W.
            LaFave & A. Scott, Handbook on Criminal Law 194 195
            (1972). Moreover, our analysis in Freed likening the Act
            to the public welfare statute in Balint rested entirely
            on the assumption that the defendant knew that he was
            dealing with hand grenades that is, that he knew he
            possessed a particularly dangerous type of weapon (one
            within the statutory definition of a firearm),
            possession of which was not entirely innocent in and of
            itself.  401 U. S., at 609. The predicate for that
            analysis is eliminated when, as in this case, the very
            question to be decided is whether the defendant must
            know of the particular characteristics that make his
            weapon a statutory firearm.

                Notwithstanding these distinctions, the Government
            urges that Freed's logic applies because guns, no less
            than grenades, are highly dangerous devices that should
            alert their owners to the probability of regulation.
            But the gap between Freed and this case is too wide to
            bridge.  In glossing over the distinction between
            grenades and guns, the Government ignores the particular
            care we have taken to avoid construing a statute to
            dispense with mens rea where doing so would criminalize
            a broad range of apparently innocent conduct.  Liparota,
            471 U. S., at 426.  In Liparota, we considered a statute
            that made unlawful the unauthorized acquisition or
            possession of food stamps. We determined that the
            statute required proof that the defendant knew his
            possession of food stamps was unauthorized, largely
            because dispensing with such a mens rea requirement
            would have resulted in reading the statute to outlaw a
            number of apparently innocent acts.  Ibid.  Our
            conclusion that the statute should not be treated as
            defining a public welfare offense rested on the common
            sense distinction that a food stamp can hardly be
            compared to a hand grenade.  Id., at 433.

                Neither, in our view, can all guns be compared to
            hand grenades.  Although the contrast is certainly not
            as stark as that presented in Liparota, the fact remains
            that there is a long tradition of widespread lawful gun
            ownership by private individuals in this country. Such a
            tradition did not apply to the possession of hand
            grenades in Freed or to the selling of dangerous drugs
            that we considered in Balint.  See also International
            Minerals, 402  U. S., at 563 565; Balint, 258 U. S., at
            254.  In fact, in Freed we construed 5861(d) under the
            assumption that one would hardly be surprised to learn
            that possession of hand grenades is not an innocent act.
            Freed, supra, at 609.  Here, the Government essentially
            suggests that we should interpret the section under the
            altogether different assumption that one would hardly be
            surprised to learn that owning a gun is not an innocent
            act.  That proposition is simply not supported by common
            experience.  Guns in general are not deleterious devices
            or products or obnoxious waste materials, International
            Minerals, supra, at 565, that put their owners on notice
            that they stand in responsible relation to a public
            danger. Dotterweich, 320 U. S., at 281.

                The Government protests that guns, unlike food
            stamps, but like grenades and narcotics, are potentially
            harmful devices.(The dissent's assertions to the
            contrary notwithstanding, the Government's position,
            [a]ccurately identified, post, at 10, is precisely that
            guns in general are dangerous items.  The Government,
            like the dissent, cites  Sipes v. United States, 321
            F.2d 174, 179 (CA8), cert. denied, 375 U. S. 913 (1963),
            for the proposition that a defendant's knowledge that
            the item he possessed was a gun is sufficient for a
            conviction under 5861(d).  Brief for United States 21.
            Indeed, the Government argues that guns should be placed
            in the same category as the misbranded drugs in
            Dotterweich and the narcotics in Balint because `one
            would hardly be surprised to learn,' Freed, 401 U. S. at
            609, that there are laws that affect one's rights of gun
            ownership.  Brief for United States 22. The dissent
            relies upon the Government's repeated contention that
            the statute requires knowledge that the item at issue
            was highly dangerous and of a type likely to be subject
            to regulation. Id., at 9. But that assertion merely
            patterns the general language we have used to describe
            the mens rea requirement in public welfare offenses and
            amounts to no more than an assertion that the statute
            should be treated as defining a public welfare offense.)





                Under this view, it seems that Liparota's
            concern for criminalizing ostensibly innocuous
            conduct is inapplicable whenever an item is
            sufficiently dangerous that is, dangerousness alone
            should alert an individual to probable regulation and
            justify treating a statute that regulates the
            dangerous device as dispensing with mens rea. But
            that an item is dangerous, in some general sense,
            does not necessarily suggest, as the Government
            seems to assume, that it is not also entirely
            innocent.  Even dangerous items can, in some cases, be
            so commonplace and generally available that we would
            not consider them to alert individuals to the
            likelihood of strict regulation.  As suggested above,
            despite their potential for harm, guns generally can
            be owned in perfect innocence.  Of course, we might
            surely classify certain categories of guns no doubt
            including the machineguns, sawed-off shotguns, and
            artillery pieces that Congress has subjected
            to regulation as items the ownership of which would
            have the same quasisuspect character we
            attributed to owning hand grenades in Freed.  But
            precisely because guns falling outside those
            categories traditionally have been widely accepted as
            lawful possessions, their destructive potential,
            while perhaps even greater than that of some items we
            would classify along with narcotics and hand
            grenades, cannot be said to put gun owners
            sufficiently on notice of the likelihood of
            regulation to justify interpreting 5861(d) as not
            requiring proof of knowledge of a weapon's
            characteristics.6

                                          
                         6The dissent asserts that the question
                      is not  whether all  guns are  deleterious
                      devices,  but whether  a gun  such  as the
                      one  possessed by petitioner,  post, at 10
                      (which  the  dissent  characterizes  as  a
                       semiautomatic  weapon  that  [is] readily
                      convertible into  a machinegun,  post,  at
                      1,  11,  19), is  such a  device.   If the
                      dissent intends to suggest that  the cate-
                      gory of  readily convertible  semiautomat-
                      ics  provides the  benchmark for  defining
                      the  knowledge  requirement  for  5861(d),
                      it  is difficult  to  see how  it  derives
                      that  class of weapons as a  standard.  As
                      explained  above,  see n.  5,  supra,  the
                      Government's  argument has  nothing to  do
                      with this  ad  hoc  category  of  weapons.
                      And   the  statute   certainly  does   not
                      suggest that  any significance should  at-
                      tach to  readily convertible  semiautomat-
                      ics, for that  class bears no  relation to
                      the definitions  in the Act.   Indeed,  in
                      the absence of any  definition, it is  not
                      at  all  clear what  the contours  of this
                      category  would  be.   The  parties assume
                      that virtually  all semiautomatics may  be
                      converted  into  automatics,  and limiting
                      the class  to those  readily   convertible
                      provides no  real guidance concerning  the
                      required mens rea.   In short, every owner










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES


                                          
                      of a semiautomatic  rifle or handgun would
                      potentially meet such a mens rea test.
                      But the  dissent apparently  does not con-
                      ceive  of  the  mens  rea  requirement  in
                      terms  of specific  categories of  weapons
                      at  all, and  rather views  it  as  a more
                      fluid  concept   that  does  not   require
                      delineation  of any  concrete elements  of
                      knowledge  that  will  apply  consistently
                      from case to  case.  The  dissent sees  no
                      need to define
                      a class  of items  the knowing  possession
                      of which  satisfies the  mens rea  element
                      of the offense, for in the  dissent's view
                      the   exact  content   of  the   knowledge
                      requirement  can be  left to  the jury  in
                      each case.  As long  as the jury concludes
                      that  the item in a given  case is  suffi-
                      ciently  dangerous to  alert  [the  defen-
                      dant]  to the  likelihood of  regulation, 
                      post,  at 15, the knowledge requirement is
                      satisfied.   See also post, at  1, 18, 19.
                      But  the  mens  rea  requirement  under  a
                      criminal statute is  a question of law, to
                      be   determined  by   the   court.     Our
                      decisions suggesting  that public  welfare
                      offenses require  that the defendant  know
                      that  he stands  in  responsible  relation
                      to  a  public  danger,   Dotterweich,  320
                      U. S.,  at 281,  in  no way  suggest  that
                      what constitutes a  public danger is a ju-
                      ry  question.   It is for  courts, through
                      interpretation of  the statute, to  define
                      the mens  rea required  for a  conviction.
                      That task cannot  be reduced to setting  a
                      general   standard,   post,  at  13,  that
                      leaves it to the jury to  determine, based
                      presumably on  the jurors' personal  opin-










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                               On  a  slightly  different  tack,
                      the  Government  suggests  that  guns  are
                      subject  to an array of regulations at the
                      federal, state, and  local levels that put
                      gun  owners on  notice that  they must de-
                      termine  the   characteristics  of   their
                      weapons   and  comply   with   all   legal
                      requirements.7   But regulation in  itself

                                          
                      ions,  whether  the  items  involved in  a
                      particular  prosecution  are  sufficiently
                      dangerous  to place a  person on notice of
                      regulation.
                      Moreover, as  our discussion above  should
                      make clear,  to determine  as a  threshold
                      matter   whether   a   particular  statute
                      defines a public  welfare offense, a court
                      must  have   in  view  some  category   of
                      dangerous  and  deleterious  devices  that
                      will  be assumed  to  alert  an individual
                      that  he stands  in  responsible  relation
                      to  a public danger.   Dotterweich, supra,
                      at 281.   The truncated mens  rea require-
                      ment we  have described applies  precisely
                      because  the court has determined that the
                      statute regulates in a  field where  know-
                      ing possession  of some  general class  of
                      items should  alert individuals to  proba-
                      ble regulation.  Under  the dissent's  ap-
                      proach, however, it seems that  every reg-
                      ulatory  statute   potentially  could   be
                      treated  as a  public  welfare  offense as
                      long as the jury not the  court ultimately
                      determines   that   the   specific   items
                      involved  in  a  prosecution  were  suffi-
                      ciently dangerous.
                         7See, e. g., 18 U. S. C.   921 928 (1-
                      988 ed. and  Supp IV) (requiring licensing
                      of manufacturers,  importers, and  dealers










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                      is not sufficient to  place gun  ownership
                      in  the category of the  sale of narcotics
                      in  Balint.  The  food stamps  at issue in
                      Liparota  were  subject  to  comprehensive
                      regulations,  yet we  did  not  understand
                      the statute there to dispense with  a mens
                      rea  requirement.   Moreover, despite  the
                      overlay of legal restrictions on  gun own-
                      ership,  we question  whether  regulations
                      on  guns are  sufficiently intrusive  that
                      they  impinge upon  the common  experience
                      that  owning a  gun  is usually  licit and
                      blameless conduct.   Roughly  50 per  cent
                      of  American homes  contain at  least  one
                      firearm  of  some sort,8  and in  the vast
                      majority of  States, buying  a shotgun  or
                      rifle is  a simple transaction that  would
                      not alert a person to regulation  any more
                      than would buying a car.9 

                                          
                      of guns  and regulating the sale,  posses-
                      sion,  and  interstate  transportation  of
                      certain guns).
                         8See U. S. Dept. of Justice,  Bureau of
                      Justice Statistics,  Sourcebook of  Crimi-
                      nal  Justice Statistics  209,  Table  2.58
                      (1992).
                         9For  example, as  of 1990,  39 States
                      allowed adult residents,  who are not fel-
                      ons or  mentally infirm, to purchase a ri-
                      fle or shotgun simply with proof  of iden-
                      tification (and in some  cases a  simulta-
                      neous  application  for a  permit).    See
                      U. S.  Dept. of Justice, Bureau of Justice
                      Statistics,   Identifying  Persons,  Other
                      Than Felons, Ineligible to Purchase  Fire-
                      arms  114,  Exh.  B.4  (1990); U. S.  Con-
                      gress,  Office  of  Technology Assessment,
                      Automated   Record   Checks   of   Firearm










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                               If  we were to accept as a gener-
                      al rule  the Government's suggestion  that
                      dangerous and regulated items place  their
                      owners under an obligation  to inquire  at
                      their peril  into compliance with  regula-
                      tions,  we would  undoubtedly  reach  some
                      untoward results.  Automobiles, for  exam-
                      ple,  might  also  be  termed   dangerous 
                      devices and  are highly  regulated at both
                      the state  and federal  levels.   Congress
                      might see  fit to  criminalize the  viola-
                      tion  of  certain  regulations  concerning
                      automobiles, and  thus  might  make  it  a
                      crime  to  operate  a  vehicle  without  a
                      properly   functioning  emission   control
                      system.   But we  probably would  hesitate
                      to conclude  on the basis  of silence that
                      Congress intended  a prison  term to apply
                      to a car owner  whose vehicle's  emissions
                      levels, wholly  unbeknownst to him,  began
                      to  exceed legal  limits  between  regular
                      inspection dates. 
                               Here, there  can be little  doubt
                      that,  as in  Liparota,  the  Government's
                      construction  of the  statute  potentially
                      would  impose  criminal  sanctions  on   a
                      class    of    persons    whose     mental
                      state ignorance of the characteristics  of
                      weapons  in their  possession makes  their


                                          
                      Purchasers 27  (July 1991).   See  also M.
                      Cooper,  Reassessing   the  Nation's   Gun
                      Laws, Editorial Research Reports 158,  160
                      (Jan.-Mar. 1991)  (table) (suggesting  the
                      total  is  forty-one  States);  Dept.   of
                      Treasury, Bureau  of Alcohol, Tobacco  and
                      Firearms, State  Laws and Published  Ordi-
                      nances Firearms (19th ed. 1989).










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                      actions entirely innocent.10  The  Govern-
                      ment does not dispute the  contention that
                      virtually any semiautomatic weapon may  be
                      converted,  either by  internal  modifica-
                      tion  or, in  some  cases, simply  by wear
                      and  tear,  into  a machinegun  within the
                      meaning of the  Act.  Cf. United States v.
                      Anderson, 885 F. 2d 1248, 1251,  1253 1254
                      (CA5  1989) (en  banc).    Such a  gun may
                      give  no  externally  visible   indication
                      that it  is fully automatic.   See  United
                      States  v.  Herbert,  698  F. 2d 981,  986
                      (CA9),   cert.  denied,   464  U. S.   821
                      (1983).   But  in the  Government's  view,
                      any  person who has  purchased what he be-
                      lieves to  be  a  semiautomatic  rifle  or
                      handgun,  or who  simply has  inherited  a
                      gun from a relative and left  it untouched
                      in  an attic  or basement,  can be subject
                      to  imprisonment, despite  absolute  igno-
                      rance  of the  gun's firing  capabilities,
                      if the gun turns  out to be  an automatic.

                               We concur in the Fifth  Circuit's
                      conclusion on this  point:  It is unthink-
                      able to  us that Congress intended to sub-
                      ject  such  law-abiding,  well-intentioned
                      citizens to  a possible  ten-year term  of
                      imprisonment if . . . what they  genuinely
                      and reasonably believed was a  convention-
                      al  semiautomatic [weapon]  turns  out  to
                      have worn down into or been  secretly mod-
                      ified  to  be  a fully  automatic weapon. 
                      Anderson, supra, at  1254.  As we noted in

                                          
                         10We, of course,  express no view con-
                      cerning  the  inferences  a jury  may have
                      drawn   regarding  petitioner's  knowledge
                      from the evidence in this case.










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                      Morissette, the   purpose and obvious  ef-
                      fect of  doing away  with the  requirement
                      of a guilty intent  is to ease  the prose-
                      cution's path to  conviction.   342 U. S.,
                      at 263.11    We  are reluctant  to  impute
                      that purpose  to Congress  where, as here,
                      it would mean  easing the path to convict-
                      ing persons  whose conduct would not  even
                      alert them  to the  probability of  strict
                      regulation in  the form of  a statute such
                      as  5861(d).

                                          
                         11The    Government    contends   that
                      Congress  intended precisely  such an  aid
                      to obtaining  convictions, because requir-
                      ing  proof  of  knowledge would  place too
                      heavy a burden  on the Government and  ob-
                      struct   the    proper   functioning    of
                       5861(d).  Cf. United  States v.  Balint,
                      258 U. S. 250, 254  (1922) (difficulty  of
                      proving  knowledge  suggests  Congress did
                      not  intend to  require  mens rea).    But
                      knowledge  can be  inferred  from  circum-
                      stantial evidence,  including any external
                      indications  signaling the  nature of  the
                      weapon.   And  firing  a  fully  automatic
                      weapon  would make  the regulated  charac-
                      teristics   of   the   weapon  immediately
                      apparent  to its owner.  In  short, we are
                      confident  that when  the defendant  knows
                      of  the characteristics of his weapon that
                      bring it within the scope  of the Act, the
                      Government will not face great  difficulty
                      in proving that knowledge.   Of course, if
                      Congress  thinks it  necessary  to  reduce
                      the  Government's   burden  at  trial   to
                      ensure proper  enforcement of  the Act, it
                      remains free to amend  5861(d) by explic-
                      itly eliminating a mens rea requirement. 










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES


                                          C
                               The  potentially  harsh   penalty
                      attached to violation  of  5861(d) up  to
                      10 years' imprisonment confirms our  read-
                      ing of the  Act.  Historically, the penal-
                      ty  imposed  under a  statute  has been  a
                      significant  consideration  in determining
                      whether  the  statute should  be construed
                      as dispensing  with mens rea.   Certainly,
                      the  cases that  first defined the concept
                      of the  public welfare offense almost uni-
                      formly  involved  statutes  that  provided
                      for only light penalties such as fines  or
                      short  jail sentences, not imprisonment in
                      the state penitentiary.  See,  e. g., Com-
                      monwealth v. Raymond, 97 Mass. 567  (1867)
                      (fine  of up  to  $200  or six  months  in
                      jail,  or  both); Commonwealth  v. Farren,
                      91  Mass.  489  (1864) (fine);  People  v.
                      Snowberger, 113  Mich.  86,  71 N. W.  497
                      (1897)  (fine of up to  $500 or incarcera-
                      tion in county jail).12  
                               As   commentators  have   pointed
                      out, the small penalties attached  to such
                      offenses  logically complemented  the  ab-
                      sence  of a  mens  rea  requirement: in  a


                                          
                         12Leading  English cases  developing a
                      parallel  theory  of  regulatory  offenses
                      similarly  involved  violations punishable
                      only by fine or short  term incarceration.
                      See, e. g., Regina v. Woodrow,  15 M. & W.
                      404, 153  Eng. Rep.  907 (Ex. 1846)  (fine
                      of   200 for  adulterated tobacco);  Hobbs
                      v. Winchester  Corp., [1910]  2 K. B.  471
                      (maximum penalty of three months'  impris-
                      onment for sale of unwholesome meat).










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                      system that generally requires a   vicious
                      will    to  establish   a  crime,   4   W.
                      Blackstone,  Commentaries  *21,   imposing
                      severe punishments  for offenses that  re-
                      quire no mens rea would  seem incongruous.
                      See  Sayre, Public  Welfare  Offenses,  33
                      Colum. L.  Rev. 55,  70  (1933).   Indeed,
                      some courts justified the absence  of mens
                      rea   in  part  on  the   basis  that  the
                      offenses   did    not   bear   the    same
                      punishments  as  infamous  crimes,   Tene-
                      ment House  Dept. v.  McDevitt, 215  N. Y.
                      160,  168,   109  N. E.   88,  90   (1915)
                      (Cardozo,  J.),  and  questioned   whether
                      imprisonment was  compatible with the  re-
                      duced culpability required for such  regu-
                      latory offenses.   See,  e. g., People  ex
                      rel.  Price  v.  Sheffield  Farms-Slawson-
                      Decker Co.,  225 N. Y. 25, 32 33, 121 N.E.
                      474,  477 (1918)  (Cardozo, J.);  id.,  at
                      35, 121 N. E.,  at 478 (Crane, J., concur-
                      ring)  (arguing that  imprisonment  for  a
                      crime  that  requires no  mens  rea  would
                      stretch the  law regarding  acts mala pro-
                      hibita beyond  its limitations).13   Simi-
                      larly, commentators  collecting the  early
                      cases  have argued  that offenses  punish-
                      able by imprisonment cannot be  understood

                                          
                         13Cf. Regina  v. Tolson,  23 Q. B., at
                      177  (Wills, J.) (In determining whether a
                      criminal statute dispenses with mens  rea,
                       the nature and extent of the penalty  at-
                      tached to  the offence  may reasonably  be
                      considered.   There is  nothing that  need
                      shock  any mind in the payment  of a small
                      pecuniary penalty  by a person who has un-
                      wittingly  done  something  detrimental to
                      the public interest ).










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                      to be  public welfare  offenses, but  must
                      require mens rea.   See R. Perkins, Crimi-
                      nal  Law 793 798 (2d ed. 1969) (suggesting
                      that the  penalty should  be the  starting
                      point  in determining  whether  a  statute
                      describes  a   public  welfare   offense);
                      Sayre,  supra, at  72 ( Crimes  punishable
                      with  prison  sentences  . . .  ordinarily
                      require proof of a guilty intent ).14
                               In  rehearsing  the  characteris-
                      tics of  the public  welfare offense,  we,
                      too,  have included  in our  consideration
                      the  punishments imposed  and  have  noted
                      that   penalties commonly  are  relatively
                      small, and  conviction does  no grave dam-
                      age   to   an   offender's    reputation. 
                      Morissette,  342 U. S., at 256.15  We have

                                          
                         14But see,  e. g., State  v. Lindberg,
                      125  Wash. 51, 215 P.  41 (1923) (applying
                      the public welfare offense rationale  to a
                      felony).
                         15See also  United States  Gypsum, 438
                      U. S., at 442,  n. 18 (noting that an  in-
                      dividual   violation    of   the   Sherman
                      Antitrust Act  is a  felony punishable  by
                      three  years  in  prison  or  a  fine  not
                      exceeding   $100,000   and   stating  that
                       [t]he  severity of  these sanctions  pro-
                      vides further  support for our  conclusion
                      that the [Act] should not be  construed as
                      creating strict-liability  crimes ).   Cf.
                      Holdridge  v.  United States,  282  F.  2d
                      302,   310  (CA8   1960)  (Blackmun,   J.)
                      ( [W]here  a   federal  criminal   statute
                      omits mention  of intent  and . . .  where
                      the  penalty is  relatively  small,  where
                      conviction  does   not  gravely  besmirch,
                      [and]  where the  statutory crime  is  not










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                      even recognized that  it was  [u]nder such
                      considerations   that  courts  have   con-
                      strued  statutes  to  dispense  with  mens
                      rea.  Ibid.
                               Our characterization of the  pub-
                      lic welfare  offense in Morissette  hardly
                      seems apt, however,  for a crime that is a
                      felony,  as is  violation  of  5861(d).16
                      After  all,  felony   is, as  we  noted in
                      distinguishing certain  common law  crimes
                      from public welfare  offenses,  `as bad a
                      word as  you can give to  man or thing.' 
                      Morissette, supra,  at 260  (quoting 2  F.
                      Pollock & F. Maitland, History  of English
                      Law  465 (2d ed.  1899)).  Close adherence
                      to the early cases  described above  might
                      suggest that  punishing a  violation as  a
                      felony  is simply  incompatible  with  the
                      theory of  the public welfare offense.  In
                      this view,  absent a clear statement  from
                      Congress that  mens rea  is not  required,
                      we  should not  apply  the  public welfare
                      offense rationale  to interpret any  stat-
                      ute  defining a felony offense as dispens-
                      ing  with mens rea.   But  see Balint, su-
                      pra.
                               We need  not adopt such a defini-
                      tive rule of construction  to decide  this
                      case,  however.   Instead,  we  note  only
                      that  where, as here, dispensing with mens
                      rea would  require the  defendant to  have

                                          
                      one taken over from the common law,  . . .
                      the statute
                      can be  construed  as  one  not  requiring
                      criminal intent ).
                         16Title  18 U. S. C.   3559  makes any
                      crime punishable by more than one  year in
                      prison a felony.










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                      knowledge  only  of  traditionally  lawful
                      conduct,  a severe  penalty is  a  further
                      factor  tending to  suggest that  Congress
                      did  not intend  to eliminate  a mens  rea
                      requirement.   In  such a  case, the usual
                      presumption  that a  defendant  must  know
                      the facts  that make  his conduct  illegal
                      should apply.

                                         III
                               In  short,  we conclude  that the
                      background rule of  the common  law favor-
                      ing  mens rea should govern interpretation
                      of  5861(d) in  this case.   Silence does
                      not  suggest that  Congress dispensed with
                      mens rea for the  element of  5861(d)  at
                      issue  here.   Thus, to  obtain a  convic-
                      tion,  the  Government  should  have  been
                      required to prove that petitioner  knew of
                      the features of  his AR 15 that brought it
                      within the scope of the Act.17


                                          
                         17In reaching  our conclusion, we find
                      it  unnecessary to  rely  on  the rule  of
                      lenity, under which an ambiguous  criminal
                      statute  is to  be construed  in  favor of
                      the accused.   That  maxim of construction
                       is  reserved for  cases  where,  `[a]fter
                       seiz[ing] every thing from which  aid can
                      be derived, ' the  Court is `left with an
                      ambiguous  statute.'     Smith v.  United
                      States, 507  U. S. ___,  ___ (1993)  (slip
                      op.,  at  16)  (quoting  United States  v.
                      Bass, 404  U. S. 336, 347  (1971), in turn
                      quoting United States v. Fisher,  2 Cranch
                      358, 386  (1805)).  See also United States
                      v.  R. L. C., 503  U. S.  ___,  ___ (1992)
                      (THOMAS, J.,  concurring in part and  con-










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                               We emphasize that our holding  is
                      a narrow one.  As in our prior  cases, our
                      reasoning  depends  upon  a   common-sense
                      evaluation of the nature  of the  particu-
                      lar device or substance Congress  has sub-
                      jected to regulation and the  expectations
                      that individuals may legitimately have  in
                      dealing  with  the regulated  items.    In
                      addition, we  think that  the penalty  at-
                      tached to  5861(d) suggests that Congress
                      did  not intend  to eliminate  a mens  rea
                      requirement for violation of the  section.
                      As  we  noted  in  Morissette,   [N]either
                      this  Court nor, so  far as  we are aware,
                      any other  has undertaken  to delineate  a
                      precise  line or  set forth  comprehensive
                      criteria   for   distinguishing    between
                      crimes that  require a  mental element and
                      crimes that do not.    342 U. S.,  at 260.
                      We  attempt no  definition  here,  either.
                      We  note  only  that  our holding  depends

                                          
                      curring  in  the  judgment);  Chapman   v.
                      United States,  500 U. S. 453, 463  (1991)
                      (rule of lenity inapplicable unless  there
                      is  a    `grievous  ambiguity  or   uncer-
                      tainty'   in  the  statute).    Here,  the
                      background rule  of the  common law favor-
                      ing mens rea  and the substantial body  of
                      precedent  we  have  developed  construing
                      statutes that do not specify a  mental el-
                      ement  provide  considerable  interpretive
                      tools  from which we  can  seize aid,  and
                      they  do not  leave us  with  the ultimate
                      impression     that       5861(d)      is
                       grievous[ly]  ambiguous.   Certainly,  we
                      have not  concluded in the past that stat-
                      utes silent with  respect to mens rea  are
                      ambiguous.  See, e. g., Balint, supra.










                                   92 1441 OPINION

                               STAPLES v. UNITED STATES

                      critically on  our view  that if  Congress
                      had  intended to make outlaws  of gun own-
                      ers who  were wholly  ignorant of the  of-
                      fending characteristics of their  weapons,
                      and  to  subject them  to  lengthy  prison
                      terms, it  would have  spoken more clearly
                      to  that effect.    Cf.  United States  v.
                      Harris, 959  F. 2d 246, 261 (CADC),  cert.
                      denied, 506 U. S. ___ (1992).
                               For  the foregoing  reasons,  the
                      judgment of  the Court of  Appeals is  re-
                      versed and  the case  remanded for further
                      proceedings consistent with this opinion.
                      So ordered. 














                    SUPREME COURT OF THE UNITED STATES
                              

                      No. 92 1441
                              
                      HAROLD E. STAPLES, III, PETITIONER v.
                      UNITED STATES

                      ON WRIT OF CERTIORARI TO THE UNITED
                      STATES COURT OF APPEALS FOR THE TENTH
                      CIRCUIT
                      [May 23, 1994]

                               JUSTICE GINSBURG, with whom  JUS-
                      TICE  O'CONNOR joins,  concurring  in  the
                      judgment.
                               The statute  petitioner Harold E.
                      Staples  is  charged  with  violating,  26
                      U. S. C.  5861(d),  makes it a crime  for
                      any person  to  receive or possess a fire-
                      arm  which  is  not  registered  to  him. 
                      Although  the word   knowingly   does  not
                      appear in the statute's text,  courts gen-
                      erally  assume  that  Congress,  absent  a
                      contrary  indication, means  to  retain  a
                      mens  rea requirement.   Ante,  at 5;  see
                      Liparota v.  United States, 471 U. S. 419,
                      426  (1985);   United  States  v.   United
                      States Gypsum Co.,  438 U. S. 422, 437 438
                      (1978).18ding in  United States v.  Freed,
                      401  U. S. 601 (1971), that  5861(d) does
                      not require  proof of  knowledge that  the






                                          










                                    92 1441 CONCUR

                               STAPLES v. UNITED STATES

                      firearm  is unregistered,  rested  on  the
                      premise  that the  defendant  indeed  knew
                      the  items  he  possessed  were hand  gre-
                      nades.     Id.,  at  607;   id.,  at   612
                      (Brennan,  J.,  concurring  in   judgment)
                      ( The  Government and the Court agree that
                      the prosecutor must prove knowing  posses-
                      sion of the items and also knowledge  that
                      the   items  possessed   were  hand   gre-
                      nades. ).
                               Conviction  under  5861(d),  the
                      Government accordingly concedes,  requires
                      proof that  Staples  knowingly   possessed
                      the machinegun.   Brief for United  States
                      23.  The  question before us is not wheth-
                      er  knowledge of  possession is  required,
                      but  what  level  of  knowledge  suffices:
                      (1) knowledge simply of possession of  the
                      object; (2)  knowledge, in addition,  that
                      the  object  is a  dangerous  weapon;  (3)
                      knowledge,  beyond dangerousness,  of  the
                      characteristics  that  render  the  object
                      subject   to  regulation,   for   example,
                      awareness   that    the   weapon   is    a
                      machinegun.19


                                          
                         19Some Courts  of Appeals have adopted
                      a variant  of the  third reading,  holding
                      that  the Government  must show  that  the
                      defendant knew  the gun  was a machinegun,
                      but  allowing inference  of the  requisite
                      knowledge  where a  visual  inspection  of
                      the  gun  would reveal  that  it  has been
                      converted into an automatic  weapon.   See
                      United States v.  O'Mara, 963 F. 2d  1288,
                      1291 (CA9  1992); United  States v. Ander-
                      son,  885 F. 2d 1248, 1251  (CA5 1989) (en
                      banc).










                                    92 1441 CONCUR

                               STAPLES v. UNITED STATES

                               Recognizing that the first  read-
                      ing effectively  dispenses with mens  rea,
                      the   Government   adopts   the    second,
                      contending  that it  avoids  criminalizing
                       apparently  innocent conduct,   Liparota,
                      supra, at  426, because  under the  second
                      reading,  a  defendant who possessed  what
                      he thought  was a  toy or  a violin  case,
                      but which in fact  was a machinegun, could
                      not  be  convicted.     Brief  for  United
                      States 23.  The Government,  however, does
                      not take  adequate account  of the   wide-
                      spread lawful gun ownership  Congress  and
                      the  States  have allowed  to  persist  in
                      this  country.  See  United States v. Har-
                      ris, 959 F.  2d 246, 261 (CADC) (per curi-
                      am), cert.  denied, 506 U. S. ___  (1992).
                      Given  the notable  lack of  comprehensive
                      regulation,   mere unregistered possession
                      of    certain    types    of    [regulated
                      weapons] often [difficult to  distinguish]
                      from  other, [non-regulated]  types,   has
                      been  held  inadequate  to  establish  the
                      requisite knowledge.   See  959 F. 2d,  at
                      261.
                               The  Nation's  legislators  chose
                      to place under a registration  requirement
                      only  a very  limited  class  of firearms,
                      those they  considered especially  danger-
                      ous.  The generally  dangerous   character
                      of  all  guns,  the  Court  therefore  ob-
                      serves, ante,  at 11 12,  did not  suffice
                      to give individuals in Staples'  situation
                      cause to inquire  about the need for  reg-
                      istration.    Compare  United  States   v.
                      Balint,  258 U. S.  250 (1922)  (requiring
                      reporting  of sale  of strictly  regulated
                      narcotics, opium  and cocaine).  Only  the
                      third  reading, then, suits the purpose of
                      the mens rea requirement to shield  people










                                    92 1441 CONCUR

                               STAPLES v. UNITED STATES

                      against  punishment for  apparently  inno-
                      cent activity.20
                               The indictment  in Staples'  case
                      charges  that he   knowingly received  and
                      possessed  firearms.  App.  to  Brief  for


                                          
                         20The  mens rea  presumption  requires
                      knowledge only  of the facts that make the
                      defendant's conduct illegal, lest it  con-
                      flict   with   the   related  presumption,
                       deeply rooted in the American  legal sys-
                      tem,  that, ordinarily,  ignorance of  the
                      law or a mistake  of law is  no defense to
                      criminal  prosecution.    Cheek v.  United
                      States,  498 U. S.  192, 199  (1990).  Cf.
                      Freed,  401 U. S.,  at  612  (Brennan, J.,
                      concurring in  judgment) ( If the  ancient
                      maxim  that  `ignorance of  the law  is no
                      excuse' has any  residual validity, it in-
                      dicates   that    the   ordinary    intent
                      requirement mens rea -of  the criminal law
                      does not  require knowledge that an act is
                      illegal,  wrong, or  blameworthy. ).   The
                      maxim  explains why  some   innocent   ac-
                      tors for  example, a  defendant who  knows
                      he  possesses  a weapon  with  all  of the
                      characteristics that subject it to  regis-
                      tration, but was  unaware of the registra-
                      tion requirement,  or thought the gun  was
                      registered may    be    convicted    under
                       5861(d), see post, at  17.  Knowledge  of
                      whether  the  gun  was  registered  is  so
                      closely related  to knowledge  of the reg-
                      istration requirement  that requiring  the
                      Government to  prove the  former would  in
                      effect require  it to  prove knowledge  of
                      the  law.   Cf. Freed,  supra, at  612 614
                      (Brennan, J., concurring in judgment).










                                    92 1441 CONCUR

                               STAPLES v. UNITED STATES

                      Appellant in No. 91 5033  (CA10), p.  1.21
                       Firearms  has  a circumscribed  statutory
                      definition.   See  26  U. S. C.   5845(a).
                      The   firear[m]  the  Government  contends
                      Staples   possessed   in   violation    of
                       5861(d)   is    a   machinegun.       See
                       5845(a)(6).   The indictment thus  effec-
                      tively  charged  that  Staples   knowingly
                      possessed a  machinegun.   Knowingly  pos-
                      sessed   logically  means   possessed  and
                      knew that  he possessed.   The  Government
                      can reconcile the jury instruction22  with

                                          
                         21 The indictment charged Staples with
                      possession     of     two     unregistered
                      machineguns,  but   the  jury  found   him
                      guilty  of knowingly  possessing only  one
                      of them.  Tr. 477.
                         22The trial court instructed the jury:
                       [A] person is  knowingly in possession of
                      a thing if his possession  occurred volun-
                      tarily and  intentionally and not  because
                      of mistake or accident  or other  innocent
                      reason.   The purpose of  adding the  word
                      `knowingly' is to insure  that no one  can
                      be convicted  of possession  of a  firearm
                      he  did  not  intend   to  possess.    The
                      Government  need not  prove the  defendant
                      knows he's dealing  with a weapon possess-
                      ing every last characteristic [which  sub-
                      jects it] to the regulation.   It would be
                      enough to prove he knows  that he is deal-
                      ing  with a dangerous device of  a type as
                      would alert one to  the likelihood of reg-
                      ulation.  If he has  such knowledge and if
                      the   particular   item   is,   in   fact,
                      regulated, then  that person  acts at  his
                      peril.       Mere    possession   of    an
                      unregistered  firearm is  a  violation  of










                                    92 1441 CONCUR

                               STAPLES v. UNITED STATES

                      the  indictment only  on  the  implausible
                      assumption that  the term  firear[m]   has
                      two different  meanings when  used once in
                      the same  charge simply  gun  when  refer-
                      ring   to  what   petitioner   knew,   and
                       machinegun   when referring  to  what  he
                      possessed.   See Cunningham, Levi, Green,
                      & Kaplan,  Plain Meaning  and Hard  Cases,
                      103 Yale  L. J.  1561, 1576 1577  (1994));
                      cf. Ratzlaf  v. United  States, 510  U. S.
                      ___ (1994)  (slip op.,  at 8)  (construing
                      statutory  term to bear same meaning  each
                      time it is called into play ).
                      For   these  reasons,   I  conclude   that
                      conviction under   5861(d) requires proof
                      that the defendant knew  he possessed  not
                      simply a gun, but  a machinegun.   The in-
                      dictment in  this case, but  not the  jury
                      instruction,   properly   described   this
                      knowledge requirement.   I therefore  con-
                      cur in the Court's judgment.











                                          
                      the law of  the United States,  and it  is
                      not  necessary for the Government to prove
                      that the  defendant knew  that the  weapon
                      in  his possession  was a  firearm  within
                      the meaning of  the statute, only  that he
                      knowingly  possessed the  firearm.     Tr.
                      465.














                    SUPREME COURT OF THE UNITED STATES
                              

                      No. 92 1441
                              
                      HAROLD E. STAPLES, III, PETITIONER v.
                      UNITED STATES

                      ON WRIT OF CERTIORARI TO THE UNITED
                      STATES COURT OF APPEALS FOR THE TENTH
                      CIRCUIT
                      [May 23, 1994]

                               JUSTICE STEVENS,  with whom  JUS-
                      TICE BLACKMUN joins, dissenting.
                               To avoid a slight possibility  of
                      injustice  to  unsophisticated  owners  of
                      machineguns  and  sawed-off  shotguns, the
                      Court has substituted its  views of  sound
                      policy  for  the  judgment  Congress  made
                      when  it enacted the National Firearms Act
                      (or Act).   Because  the Court's  addition
                      to  the  text of  26 U. S. C.   5861(d) is
                      foreclosed  by  both  the statute  and our
                      precedent, I respectfully dissent. 
                               The  Court  is  preoccupied  with
                      guns that   generally can be owned in per-
                      fect  innocence.    Ante,  at  11.    This
                      case,  however,  involves  a semiautomatic
                      weapon that  was readily convertible  into
                      a machinegun a weapon  that the jury found
                      to be  `a dangerous  device of a type  as
                      would alert one to the likelihood  of reg-
                      ulation.'    Ante, at  3.  These are  not
                      guns   of some sort  that can  be found in










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      almost   50 percent  of  American  homes. 
                      Ante, at 13.23ly dangerous indeed, a  sub-
                      stantial  percentage of  the  unregistered
                      machineguns  now in  circulation are  con-
                      verted semiautomatic weapons.24
                               The question presented is  wheth-
                      er the  National Firearms  Act imposed  on
                      the Government  the burden of proving  be-
                      yond a reasonable doubt  not only that the
                      defendant  knew he  possessed a  dangerous
                      device sufficient to alert him  to regula-
                      tion, but  also that  he knew  it had  all
                      the  characteristics  of  a   firearm   as
                      defined in  the statute.  Three  unambigu-
                      ous guideposts  direct us  to the  correct
                      answer to  that  question:  the  text  and
                      structure of  the Act, our cases  constru-
                      ing both  this Act  and similar regulatory
                      legislation,  and the  Act's  history  and
                      interpretation.
                                          I
                               Contrary  to the assertion by the
                      Court, the  text of the  statute does pro-


                                          

                         37The  Court's and  JUSTICE GINSBURG's
                      reliance  upon Liparota is misplaced.  An-
                      te,  at 9 11; ante, at 2 3.   Although the
                      Court is  usually concerned with fine  nu-
                      ances  of statutory  text, its  discussion
                      of Liparota simply ignores  the fact  that
                      the  food stamp  fraud  provision,  unlike
                       5861(d), contained  the word  knowingly. 
                      The  Members of the Court in Liparota dis-
                      agreed on the proper interpretation.   The
                      dissenters accepted  the Government's view
                      that the term merely  required proof  that
                      the defendant  had knowledge of the  facts
                      that   constituted   the   crime.      See
                      Liparota,  471 U. S.,  at 442 443  (White,










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      vide   explicit guidance  in  this  case. 
                      Cf. ante, at 4.   The relevant  section of
                      the  Act makes it  unlawful for any person
                      . . . to  receive  or  possess  a  firearm
                      which is  not  registered  to him  in  the
                      National Firearms Registration and  Trans-
                      fer Record.    26 U. S. C.  5861(d).  Sig-
                      nificantly,   the  section   contains   no
                      knowledge   requirement,   nor   does   it
                      describe a common-law crime.
                               The common law generally did  not
                      condemn  acts as criminal unless the actor
                      had  an evil  purpose or mental culpabili-
                      ty,   Morissette  v.  United  States,  342
                      U. S.  246, 252  (1952), and was  aware of
                      all the facts  that made  the conduct  un-
                      lawful.    United States  v.  Balint,  258
                      U. S.  250, 251 252 (1922).  In interpret-
                      ing  statutes  that  codified  traditional
                      common-law offenses,  courts usually  fol-
                      lowed this  rule, even  when  the text  of
                      the    statute    contained    no     such
                      requirement.   Ibid.  Because the  offense
                      involved  in this case is entirely a crea-
                      ture of statute, however,  the  background
                      rules of the  common law,  cf. ante, at 5,
                      do not require a particular  construction,
                      and   critically   different   rules    of
                      construction  apply.   See  Morissette  v.
                      United  States,  342  U. S.  246,  252 260
                      (1952).
                               In  Morissette,  Justice  Jackson
                      outlined one such interpretive rule:
                          [C]ongressional silence  as to  mental
                         elements  in  an  Act  merely  adopting
                         into  federal  statutory law  a concept
                         of  crime already . . . well defined in
                         common  law and  statutory  interpreta-
                         tion  by the  states may  warrant quite

                                          
                      J.,    dissenting)    ( I    would    read
                       2024(b)(1) . . . to  require awareness of
                      only   the  relevant   aspects  of   one's
                      conduct
                      rendering it illegal, not the fact  of il-
                      legality ).   The majority, however,  con-
                      cluded  that    knowingly   also  connoted
                      knowledge of illegality.  Id.,  471 U. S.,
                      at 424 425.   Because neither   knowingly 
                      nor   any  comparable   term  appears   in
                       5861(d), the statute before us  today re-
                      quires even  less proof  of knowledge than
                      the  dissenters  would  have  demanded  in
                      Liparota.










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                         contrary inferences  than the same  si-
                         lence  in creating  an offense  new  to
                         general law,  for whose definition  the
                         courts  have  no  guidance  except  the
                         Act.   Id., at 262.

                      Although the lack of an  express knowledge
                      requirement  in  5861(d)  is not  disposi-
                      tive, see United States  v. United  States
                      Gypsum  Co., 438  U. S. 422,  438  (1978),
                      its  absence suggests  that  Congress  did
                      not  intend to require  proof that the de-
                      fendant knew all  of the  facts that  made
                      his conduct illegal.25
                               The  provision's  place  in   the
                      overall statutory  scheme, see Crandon  v.
                      United  States, 494 U. S. 152, 158 (1990),
                      confirms this  intention.   In 1934,  when
                      Congress originally  enacted the  statute,
                      it limited the coverageof  the 1934 Act to
                      a  relatively narrow  category of  weapons
                      such  as   submachineguns  and   sawed-off
                      shotguns weapons  characteristically  used
                      only  by professional  gangsters  like  Al

                                          
                         25The Seventh  Circuit's comment  in a
                      similar case is  equally apt  here:    The
                      crime   is   possessing   an  unregistered
                      firearm not `knowingly'  possessing an un-
                      registered firearm, or possessing a  weap-
                      on  knowing  it   to  be  a  firearm,   or
                      possessing a firearm  knowing it to be un-
                      registered.  . . . .  [Petitioner's]  pro-
                      posal is not  that we  interpret a  knowl-
                      edge  or intent  requirement in   5861(d);
                      it is that we invent  one.   United States
                      v.  Ross, 917 F. 2d 997,  1000 (1990) (per
                      curiam) (emphasis in original), cert.  de-
                      nied, 498 U. S. 1122 (1991).










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      Capone,  Pretty   Boy  Floyd,  and   their
                      henchmen.26  At  the time,  the Act  would
                      have had  little application  to guns used
                      by  hunters or guns  kept at  home as pro-
                      tection  against  unwelcome   intruders.27
                      Congress therefore  could reasonably  pre-
                      sume that a  person found in possession of
                      an  unregistered machinegun  or  sawed-off
                      shotgun intended  to use  it for  criminal
                      purposes.   The  statute as  a whole,  and

                                          
                         26 The  late  1920s  and  early  1930s
                      brought  . . .  a  growing  perception  of
                      crime both  as a  major problem  and as  a
                      national   one. . . .   [C]riminal   gangs
                      found the submachinegun (a fully  automat-
                      ic, shoulder-fired  weapon utilizing auto-
                      matic  pistol  cartridges)  and  sawed-off
                      shotgun deadly  for close-range fighting. 
                      Hardy,  The  Firearms  Owners'  Protection
                      Act: A  Historical and Legal  Perspective,
                      17 Cumb. L. Rev. 585, 590 (1987).
                         27The  Senate   Report  on   the  bill
                      explained:  The  gangster as a law  viola-
                      tor must be deprived  of his most  danger-
                      ous weapon, the  machinegun.  Your commit-
                      tee is of  the opinion  that limiting  the
                      bill to  the taxing of  sawed-off guns and
                      machineguns  is sufficient  at this  time.
                      It  is not thought necessary to  go so far
                      as to  include pistols  and revolvers  and
                      sporting arms.   But while there is justi-
                      fication  for permitting  the  citizen  to
                      keep  a  pistol or  revolver  for  his own
                      protection without  any restriction, there
                      is  no reason why anyone except  a law of-
                      ficer should  have a  machinegun or sawed-
                      off  shotgun.    S.  Rep.  No.  1444,  73d
                      Cong., 2d Sess., 1 2 (1934).










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      particularly the  decision to  criminalize
                      mere possession,  reflected a  legislative
                      judgment that  the likelihood of  innocent
                      possession of such an unregistered  weapon
                      was remote, and far less  significant than
                      the  interest in  depriving  gangsters  of
                      their use.
                               In addition,  at the time of  en-
                      actment, this Court had already  construed
                      comparable  provisions  of  the   Harrison
                      Anti-Narcotic Act not to require  proof of
                      knowledge of  all the  facts that  consti-
                      tute  the  proscribed  offense.     United
                      States v. Balint, 258 U. S.  250 (1922).28
                      Indeed,    Attorney    General    Cummings
                      expressly advised  Congress that the  text
                      of  the gun  control legislation  deliber-
                      ately followed  the language  of the Anti-
                      Narcotic Act  to reap the benefit of cases
                      construing it.29   Given the reasoning  of

                                          
                         28In    the   Balint    case,    after
                      acknowledging the  general common-law rule
                      that made knowledge  of the facts an  ele-
                      ment of every  crime, we held  that as  to
                      statutory crimes  the question  is one  of
                      legislative  intent, and  that  the  Anti-
                      Narcotic Act  should be  construed to  au-
                      thorize   punishment of  a  person  for an
                      act in violation  of law[, even]  when ig-
                      norant  of   the  facts   making  it  so. 
                      Balint, 258 U. S.,  at 251 252.  The  pol-
                      icy of the law may,  in order to stimulate
                      proper  care, require  the  punishment  of
                      the negligent  person though  he be  igno-
                      rant of the  noxious character of what  he
                      sells.   Id., at 253.
                         29See National Firearms Act:  Hearings
                      on H. R.  9066 before the House  Committee










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      Balint, we  properly may  infer that  Con-
                      gress did not intend  the Court to  read a
                      stricter  knowledge requirement  into  the
                      gun control legislation  than we read into
                      the Anti-Narcotic Act.  Cannon  v. Univer-
                      sity of  Chicago, 441  U. S. 677,  698 699
                      (1979).
                               Like  the 1934  Act, the  current
                      National  Firearms Act is primarily a reg-
                      ulatory measure.  The statute  establishes
                      taxation,  registration,  reporting,   and
                      record-keeping      requirements       for
                      businesses   and   transactions  involving
                      statutorily    defined    firearms,    and
                      requires that  each firearm be  identified
                      by   a  serial   number.      26  U. S. C.
                        5801 5802,  5811 5812, 5821 5822,  5842 
                      5843.  The Secretary of the  Treasury must
                      maintain a central registry that  includes
                      the  names  and addresses  of  persons  in
                      possession of all firearms not  controlled
                      by the Government.   5841.  Congress  also
                      prohibited  certain  acts  and  omissions,
                      including  the possession  of an  unregis-
                      tered firearm.30   5861.

                                          
                      on Ways and Means, 73d  Cong., 2d Sess., 6
                      (1934).
                         30 Omission of a mental element is the
                      norm for  statutes designed  to deal  with
                      inaction.   Not registering  your gun, not
                      cleaning up your warehouse, United  States
                      v. Park,  421 U. S. 658 . . . (1975),  and
                      like  `acts' are  done  without  thinking.
                      Often the omission  occurs because of lack
                      of attention. . . . Yet  Congress may have
                      sound  reasons for requiring people to in-
                      vestigate and act, objectives that  cannot
                      be achieved if  the courts add mental ele-










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                               As the Court acknowledges,  ante,
                      at  7,  to  interpret  statutory  offenses
                      such as   5861(d), we look  to  the nature
                      of the statute  and the particular charac-
                      ter of  the items regulated  to  determine
                      the level  of knowledge  required for con-
                      viction.   An examination  of  5861(d)  in
                      light of  our precedent dictates that  the
                      crime  of possession  of  an  unregistered
                      machinegun is  in a  category of  offenses
                      described  as  public  welfare   crimes.31
                      Our decisions  interpreting such  offenses
                      clearly  require affirmance  of  petition-
                      er's conviction.
                                          II
                                Public  welfare  offenses  share
                      certain  characteristics: (1)  they  regu-
                      late   dangerous or deleterious devices or
                      products  or obnoxious  waste  materials, 
                      see  United States v. International Miner-
                      als  & Chemical Corp.,  402 U. S. 558, 565
                      (1971); (2)  they  heighten the duties  of
                      those    in    control    of    particular
                      industries, trades, properties or  activi-


                                          
                      ments to the statutes.    Ross, 917 F. 2d,
                      at 1000.
                         31These   statutes    are    sometimes
                      referred   to    as    strict   liability 
                      offenses.    As  the Court  notes, because
                      the defendant  must know  that  he is  en-
                      gaged  in the  type of  dangerous  conduct
                      that is likely  to be  regulated, the  use
                      of   the  term    strict   liability    to
                      describe  these  offenses  is  inaccurate.
                      Ante, at  7, n. 3.   I  therefore use  the
                      term  public welfare offense  to  describe
                      this type of statute.










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      ties that affect  public health, safety or
                      welfare,  Morissette,  342 U. S., at  254;
                      and  (3) they  depend on no mental element
                      but consist  only  of  forbidden  acts  or
                      omissions,  id., at 252 253.   Examples of
                      such offenses  include Congress'  exertion
                      of  its power  to  keep  dangerous narcot-
                      ics,32 hazardous substances,33 and  impure
                      and adulterated  foods and drugs34of  com-
                      merce.35
                               Public  welfare  statutes  render
                      criminal   a type  of conduct  that a rea-
                      sonable person should know  is subject  to
                      stringent public regulation and may  seri-
                      ously threaten  the community's health  or
                      safety.    Liparota  v. United States, 471
                      U. S. 419,  433 (1985).   Thus, under such
                      statutes,   a defendant  can be  convicted
                      even though  he was unaware of the circum-
                      stances of his conduct that made  it ille-

                                          
                         32See  United  States  v.  Balint, 258
                      U. S. 250 (1922).
                         33See  United States  v. International
                      Minerals &  Chemical Corp.,  402 U. S. 558
                      (1971).

                         48Although I disagree with the  assump-
                      tion   that     widespread   lawful    gun
                      ownership   provides  a  sufficient reason
                      for  believing that  there is  no need  to
                      register  guns (there  is also  widespread
                      lawful  automobile ownership),  acceptance
                      of that  assumption neither justifies  the
                      majority's  holding   nor  contradicts  my
                      conclusion on the facts of this case.










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      gal.   Id.,  at 443, n. 7 (White, J., dis-
                      senting).  Referring to the  strict crimi-
                      nal  sanctions for  unintended  violations
                      of the food and drug laws,  Justice Frank-
                      furter wrote:
                          The  purposes of this legislation thus
                         touch phases  of the  lives and  health
                         of  people which,  in the circumstances
                         of  modern industrialism,  are  largely
                         beyond  self-protection.    Regard  for
                         these purposes should infuse  construc-
                         tion of the legislation if it is  to be
                         treated  as  a  working  instrument  of
                         government and not merely as a  collec-
                         tion   of  English  words. . . .    The
                         prosecution  . . . is  based on  a  now
                         familiar  type of  legislation  whereby
                         penalties  serve as  effective means of
                         regulation.        Such     legislation
                         dispenses    with    the   conventional
                         requirement        for         criminal
                         conduct awareness  of some  wrongdoing.
                         In the  interest of the  larger good it
                         puts the  burden  of  acting at  hazard
                         upon  a  person otherwise  innocent but
                         standing  in responsible  relation to a
                         public   danger.     United  States  v.
                         Dotterweich,  320  U. S.  277,  280 281
                         (1943)   (citing   United   States   v.
                         Balint,  258  U. S. 250  (1922);  other
                         citations omitted).

                               The    National   Firearms    Act
                      unquestionably  is a  public welfare stat-
                      ute.   United States v.  Freed, 401  U. S.
                      601, 609  (1971) (holding that this  stat-
                      ute  is  a regulatory measure  in the  in-
                      terest of the  public safety ).   Congress
                      fashioned  a  legislative scheme  to regu-
                      late  the commerce  and possession of cer-










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      tain types  of dangerous devices,  includ-
                      ing specific kinds of weapons,  to protect
                      the health  and welfare  of the citizenry.
                      To enforce  this scheme, Congress  created
                      criminal  penalties  for  certain  actsand
                      omissions.  The  text of some of these of-
                      fenses    including  the   one  at   issue
                      here contains no knowledge requirement.
                               The Court recognizes:
                          [W]e have reasoned  that as long as  a
                         defendant  knows  that  he  is  dealing
                         with a  dangerous device of a character
                         that  places him  `in responsible rela-
                         tion  to a public danger,' Dotterweich,
                         supra, at 281, he  should be alerted to
                         the probability  of strict  regulation,
                         and we have assumed that in  such cases
                         Congress  intended to  place the burden
                         on the  defendant to `ascertain at  his
                         peril  whether   [his  conduct]   comes
                         within  the inhibition of the statute.'
                         Balint, supra, at 254.   Ante, at 7.

                      We thus have read a  knowledge requirement
                      into  public  welfare  crimes, but  not  a
                      requirement  that  the defendant  know all
                      the facts  that make his conduct  illegal.
                      Although  the   Court  acknowledges   this
                      standard, it  nevertheless concludes  that
                      a gun  is not the type of dangerous device
                      that  would alert  one to  the possibility
                      of regulation.
                               Both   the  Court   and   JUSTICE
                      GINSBURG  erroneously rely  upon the  tra-
                      dition[al]   innocence of gun ownership to
                      find that Congress must have  intended the
                      Government  to prove  knowledge of all the
                      characteristics   that  make  a  weapon  a
                      statutory   firear[m].    Ante,  at 10 12;
                      ante, at 2 3 (GINSBURG, J., concurring  in










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      judgment).   We  held  in  Freed, however,
                      that a   5861(d) offense may be  committed
                      by  one with no awareness of either wrong-
                      doing or of all the facts  that constitute
                      the  offense.36   401 U. S.,  at  607 610.
                      Nevertheless,  the Court,  asserting that
                      the   Government    gloss[es]   over   the
                      distinction  between grenades  and  guns, 
                      determines  that  the  gap  between  Freed
                      and  this  case  is too  wide  to bridge. 
                      Ante,  at 9.   As such,  the Court instead
                      reaches the  rather surprising  conclusion
                      that  guns  are  more  analogous  to  food
                      stamps than to hand  grenades.37  Even  if

                                          
                         36Freed,  401 U. S.,  at  607 (holding
                      that  a  violation   of   5861(d)  may  be
                      established without proof that the  defen-
                      dant was aware of the  fact that the fire-
                      arm he possessed was  unregistered).   Our
                      holding  in Freed is thus squarely at odds
                      with  the Court's conclusion that the  de-
                      fendant must  know the facts that make his
                      conduct illegal,  ante, at 19.
                         37The  Court's and  JUSTICE GINSBURG's
                      reliance upon Liparota  is misplaced.  An-
                      te,  at 9 11; ante, at 2 3.   Although the
                      Court is  usually concerned  with fine nu-
                      ances  of statutory  text, its  discussion
                      of Liparota  simply ignores the fact  that
                      the  food stamp  fraud  provision,  unlike
                       5861(d), contained  the word  knowingly. 
                      The Members of the Court in Liparota  dis-
                      agreed  on the proper interpretation.  The
                      dissenters accepted  the Government's view
                      that the  term merely required proof  that
                      the defendant  had knowledge  of the facts
                      that   constituted   the   crime.      See
                      Liparota,  471 U. S.,  at 442 443  (White,










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      one accepts that dubious proposition,  the
                      Court  founds it  upon a  faulty  premise:
                      its     mischaracterization     of     the
                      Government's submission as one  contending
                      that  all guns . . . are dangerous  devic-
                      es that put gun owners on  notice . . . . 
                      Ante, at 8  (emphasis added).38  Accurate-
                      ly identified,  the Government's  position
                      presents  the question  whether guns  such
                      as  the one possessed by petitioner  `are
                      highly  dangerous  offensive  weapons,  no
                      less  dangerous than  the  narcotics'  in
                      Balint or the hand grenades in  Freed, see
                      ante, at 8,  (quoting Freed, 401 U. S., at
                      609).39

                                          
                      J.,    dissenting)    ( I    would    read
                       2024(b)(1) . . . to  require awareness of
                      only   the  relevant   aspects  of   one's
                      conduct
                      rendering  it illegal, not the fact of il-
                      legality ).   The majority, however,  con-
                      cluded  that    knowingly   also  connoted
                      knowledge of illegality.  Id.,  471 U. S.,
                      at 424 425.   Because neither   knowingly 
                      nor   any  comparable   term  appears   in
                       5861(d), the statute before us  today re-
                      quires even  less proof  of knowledge than
                      the  dissenters  would  have  demanded  in
                      Liparota.
                         38JUSTICE  GINSBURG  similarly assumes
                      that the  character of   all guns   cannot
                      be said to place upon defendants an  obli-
                      gation   to  inquire  about  the need  for
                      registration.    Ante,  at  2 3  (emphasis
                      added).
                         39The Government  does note  that some
                      Courts of Appeals have  required proof  of
                      knowledge  only that   the weapon  was  `a










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES


                                          
                      firearm,  within  the  general  meaning of
                      that  term,'   Brief  for  United  States
                      24 25  (citing  cases).   Contrary to  the
                      assertion by the Court ante, at  11, n. 5,
                      however, the Government  does not  advance
                      this  test  as  the  appropriate knowledge
                      requirement, but instead  supports the one
                      used  by other Courts of Appeals.  Compare
                      the    Court's    description    of    the
                      Government's  position,  ibid.,  with  the
                      following  statements in  the Government's
                      brief:

                       A defendant may be  convicted of such of-
                      fenses so  long as  the government  proves
                      that he knew the item at issue  was highly
                      dangerous and of a type likely to  be sub-
                      ject  to regulation.    Brief  for  United
                      States 9.
                       [T]he   court   of   appeals    correctly
                      required  the  government  to  prove  only
                      that petitioner knew  that he  possessed a
                      dangerous weapon  likely to be subject  to
                      regulation.   Id., at 13.
                       B.  The  Intent Requirement Applicable To
                      Section
                           5861(d)  Is  Knowledge  That  One  Is
                      Dealing With
                           A Dangerous  Item Of A Type Likely To
                      Be Subject
                           To Regulation   Id., at 16.

                       But  where a  criminal  statute  involves
                      regulation   of    a   highly    hazardous
                      substance and especially  where it  penal-
                      izes a failure to  act or to comply with a
                      registration    scheme the     defendant's
                      knowledge that he  was dealing with such a










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                           Thus,  even assuming  that the  Court
                      is correct that the  mere possession of an
                      ordinary rifle  or pistol  does not entail
                      sufficient danger  to  alert  one  to  the
                      possibility     of    regulation,     that
                      conclusion  does not  resolve  this  case.
                      Petitioner knowingly  possessed a  semiau-

                                          
                      substance and  that  it was  likely to  be
                      subject  to regulation provides sufficient
                      intent to  support a conviction.   Id., at
                      17 18.  

                       Rather,  absent  contrary   congressional
                      direction,   knowledge   of   the   highly
                      dangerous nature of the articles  involved
                      and the  likelihood that  they are subject
                      to regulation  takes the place of the more
                      rigorous knowledge requirement  applicable
                      where  apparently  innocent  and  harmless
                      devices are subject  to regulation.   Id.,
                      at 20.
                       But the instruction  did not  require the
                      government to  prove that  petitioner knew
                      his weapon  `possess[ed] every  last char-
                      acteristic [which  subjects it] to regula-
                      tion'; he need only have `know[n] that  he
                      [was]  dealing with  a dangerous device of
                      a type as  would alert one  to the likeli-
                      hood of regulation.'  Tr. 465.
                       That   instruction  accurately  describes
                      the   mental   state   necessary   for   a
                      violation of  Section 5861(d).    Id.,  at
                      23.
                       [P]roof  that a defendant was on fair no-
                      tice that the item he possessed  was high-
                      ly dangerous  and likely  to be  regulated
                      is  sufficient to  support a  conviction. 
                      Id., at 24.










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      tomatic weapon  that was readily  convert-
                      ible into a  machinegun.  The  `character
                      and   nature'   of   such  a   weapon  is
                      sufficiently hazardous  to place the  pos-
                      sessor  on notice  of the  possibility  of
                      regulation.   See Posters `N' Things, Ltd.
                      v. United States,  ___ U. S. ___, ___ (19-
                      94)   (slip   op.,   at   12)    (citation
                      omitted).40    No  significant  difference

                                          
                         40The   Court  and   JUSTICE  GINSBURG
                      apparently  assume that  the outer  limits
                      of any such notice can  be no broader than
                      the  category of  dangerous  objects  that
                      Congress delineated as  firearms.    Ante,
                      at  11;  ante,  at 2 3.    Our  holding in
                      Posters `N' Things, illustrates the  error
                      in that  assumption.   A retailer  who may
                      not
                      know whether certain merchandise is  actu-
                      ally drug  paraphernalia, as that term  is
                      defined in  the relevant federal  statute,
                      may nevertheless violatethe law if   aware
                      that customers  in general  are likely  to
                      use  the  merchandise  with  drugs.    ___
                      U.S., at ___ (slip op., at 11).  The  own-
                      er  of  a  semiautomatic  weapon  that  is
                      readily convertible into a machinegun  can
                      certainly be  aware of  its dangerous  na-
                      ture  and the  consequent  probability  of
                      regulation   even  if  he  does  not  know
                      whether the weapon  is actually a machine-
                      gun.  If ignorance of the precise  charac-
                      teristics  that render  an item  forbidden
                      should  be a defense, items that are like-
                      ly to be  drug paraphernalia  are  no more
                      obviously dangerous,  and thus  regulated,
                      than   items  that   are   likely   to  be
                       firearms. 










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      exists between imposing upon the  possess-
                      or  a  duty to  determine  whether  such a
                      weapon  is registered,  Freed, 401  U. S.,
                      at 607 610, and imposing a duty  to deter-
                      mine  whether that  weapon has  been  con-
                      verted into a machinegun.
                           Cases arise,  of course,  in which  a
                      defendant  would not  know that  a  device
                      was  dangerous unless he knew  that it was
                      a  firearm  as  defined in the Act.  Freed
                      was  such  a case;  unless  the  defendant
                      knew  that the  device  in question  was a
                      hand  grenade, he  would  not  necessarily
                      have known  that it  was  dangerous.   But
                      given the text and nature of the  statute,
                      it   would  be   utterly  implausible   to
                      suggest that  Congress intended the  owner
                      of a  sawed-off shotgun  to be  criminally
                      liable if  he  knew  its barrel  was  17.5
                      inches long but  not if he mistakenly  be-
                      lieved  the   same  gun   had  an  18-inch
                      barrel.   Yet  the  Court's  holding today
                      assumes   that  Congress   intended   that
                      bizarre result.
                           The  enforcement  of  public  welfare
                      offenses always  entails some  possibility
                      of injustice.   Congress nevertheless  has
                      repeatedly  decided  that  an   overriding
                      public interest  in health  or safety  may
                      outweigh that risk when  a person is deal-
                      ing  with products  that are  sufficiently
                      dangerous or  deleterious to make it  rea-
                      sonable to  presume that  he either knows,
                      or  should know,  whether  those  products
                      conform  to  special  regulatory  require-
                      ments.    The  dangerous character  of the
                      product is reasonably presumed to  provide
                      sufficient  notice of  the probability  of
                      regulation to  justify strict  enforcement










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      against  those who  are  merely  guilty of
                      negligent rather than willful misconduct.
                           The National  Firearms Act is  within
                      the  category of  public welfare  statutes
                      enacted  by Congress  to  regulate  highly
                      dangerous items.   The Government  submits
                      that  a conviction  under  such  a statute
                      may be supported by proof that the  defen-
                      dant  knew the  item at  issue was  highly
                      dangerous and of  a type likely to be sub-
                      ject  to regulation.    Brief  for  United
                      States  9.41   It  is undisputed  that the
                      evidence in this case  met that  standard.
                      Nevertheless, neither  JUSTICE THOMAS  for
                      the   Court  nor   JUSTICE  GINSBURG   has
                      explained    why    such    a    knowledge
                      requirement is unfaithful to our  cases or
                      to the text of  the Act.42   Instead, fol-

                                          
                         41As a matter of law, this is the lev-
                      el of  knowledge required by the  statute.
                      Therefore,   contrary   to   the   Court's
                      suggestion  ante, at  12 13, n.  6, I have
                      not left  the determination of the   exact
                      content of  the knowledge requirement   to
                      the  jury.   I only leave to  the jury its
                      usual  function: the  application of  this
                      legal  standard to the facts.  In perform-
                      ing this  function, juries are  frequently
                      required  to determine  if a  law has been
                      violated  by  application  of just  such a
                       general `standard.'   See, e.g., Posters
                      `N'  Things, ___  U. S. at ___  (slip op.,
                      at  11 12);  Miller  v.  California,   413
                      U. S. 15, 24 (1973).
                         42The Court  also supports its conclu-
                      sion  on   the  basis   of  the  purported
                      disparity between the penalty provided  by
                      this statute and those of  other regulato-










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      lowing the approach of  their decision  in
                      United States v.  Harris, 959  F. 2d  246,
                      260 261   (CADC)   (per   curiam),   cert.
                      denied, sub nom. Smith  v. United  States,
                      506  U. S. ___  (1992), they  have  simply
                      explained  why,  in  their  judgment,   it
                      would be  unfair to  punish the  possessor
                      of this machinegun.
                                         III
                           The  history  and  interpretation  of
                      the  National  Firearms Act  supports  the
                      conclusion  that  Congress did  not intend
                      to  require  knowledge of  all  the  facts
                      that  constitute the offense of possession
                      of an  unregistered  weapon.   During  the
                      first  30 years of enforcement of the 1934


                                          
                      ry offenses.   Although  a modest  penalty
                      may  indicate  that a  crime  is  a public
                      welfare offense,  such a  penalty is  not,
                      as the Court recognizes ante, at  16 17, a
                      requisite    characteristic    of   public
                      welfare offenses.  For example,  the crime
                      involved in Balint involved punishment  of
                      up  to  five  years'  imprisonment.    See
                      Dotterweich, 320  U. S., at 285; see  also
                      Morissette,  342 U. S., at 251, n. 8 (not-
                      ing that rape of one too young to
                      consent is an  offense  in which  the vic-
                      tim's   actual   age   was   determinative
                      despite   defendant's   reasonable  belief
                      that  the  girl had  reached  age of  con-
                      sent ).   Moreover, congressional authori-
                      zation of  a  range of  penalties in  some
                      cases petitioner,  for   instance,  is  on
                      probation demonstrates a recognition  that
                      relatively  innocent   conduct  should  be
                      punished less severely.










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      Act, consistent  with  the  absence  of  a
                      knowledge   requirement   and   with   the
                      reasoning  in  Balint,  courts   uniformly
                      construed it not to  require knowledge  of
                      all  the  characteristics  of  the  weapon
                      that brought it  within the statute.  In a
                      case decided in 1963, then-Judge  Blackmun
                      reviewed the  earlier cases and  concluded
                      that  the defendant's  knowledge  that  he
                      possessed a  gun  was   all  the  scienter
                      which  the statute  requires.    Sipes  v.
                      United States,  321 F. 2d  174, 179 (CA8),
                      cert. denied, 375 U. S. 913 (1963).
                           Congress  subsequently  amended   the
                      statute  twice, once in  1968 and again in
                      1986.   Both  amendments  added  knowledge
                      requirements  to  other  portions  of  the
                      Act,43 but neither  the text nor the  his-
                      tory of either  amendment discloses an in-

                                          
                         43Significantly, in 1968, Congress in-
                      cluded   a    knowledge   requirement   in
                       5861(l).   26  U. S. C.  5861(l)  (making
                      it unlawful  to make, or cause  the making
                      of, a false  entry on any application, re-
                      turn, or record  required by this chapter,
                      knowing such  entry to be false )  (empha-
                      sis  added).    [W]here Congress  includes
                      particular
                      language in one  section of a  statute but
                      omits it  in another section  of the  same
                      Act,   it  is   generally  presumed   that
                      Congress acts  intentionally and purposely
                      in the disparate inclusion or  exclusion. 
                      Rodriguez  v.  United  States,  480  U. S.
                      522, 525 (1987) (internal quotation  marks
                      and citations omitted); see also  Lawrence
                      County v.  Lead-Deadwood School Dist.  No.
                      40 1, 469 U. S. 256, 267 268 (1985).










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      tent to add any  other knowledge  require-
                      ment to the possession of  an unregistered
                      firearm offense.   Given  that, with  only
                      one  partial  exception,44  every  federal
                      tribunal to address the question  had con-
                      cluded that proof of knowledge of  all the
                      facts  constituting a  violation  was  not
                      required    for   a    conviction    under
                       5861(d),45  we may  infer  that  Congress

                                          
                         44United  States v. Herbert, 698 F. 2d
                      981,  986 987  (CA9),  cert.  denied,  464
                      U. S.    821    (1983)    (requiring   the
                      Government to prove knowledge  of all  the
                      characteristics of  a weapon only when  no
                      external signs  indicated that the  weapon
                      was a  firearm ).   Not until  1989 did  a
                      Court of  Appeals adopt  the  view of  the
                      majority  today.    See  United States  v.
                      Williams, 872 F. 2d 773 (CA6).
                         45See,   e.g.,   United   States    v.
                      Gonzalez,  719  F. 2d  1516,  1522   (CA11
                      1983),  cert.   denied,  465  U. S.   1037
                      (1984);  Morgan  v.  United  States,   564
                      F. 2d  803,  805 806  (CA8  1977);  United
                      States v. Cowper, 503  F. 2d 130,  132 133
                      (CA6 1974),  cert. denied,  420 U. S.  930
                      (1975); United  States v.  De Bartolo, 482
                      F. 2d 312, 316 (CA1  1973); United  States
                      v.  Vasquez,  476 F. 2d  730,  732  (CA5),
                      cert.  denied, 414 U. S. 836 (1973), over-
                      ruled by  United States  v. Anderson,  885
                      F. 2d 1248 (CA5 1989) (en banc).
                      And,  as  I  have  already  noted,  United
                      States  v. Freed,  401  U. S.  601 (1971),
                      was consistent  with the Government's  po-
                      sition  here.  Although the Government ac-
                      cepted the  burden of  proving that  Freed
                      knew  that the  item  he  possessed was  a










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      intended that  interpretation to  survive.
                      See Lorillard v. Pons,  434 U. S. 575, 580
                      (1978).
                           In   short,   petitioner's  knowledge
                      that he  possessed an item that was suffi-
                      ciently  dangerous  to  alert  him to  the
                      likelihood of  regulation would have  sup-
                      ported a conviction during the  first half
                      century  of enforcement  of this  statute.
                      Unless application of that  standard to  a
                      particular case  violates the Due  Process
                      Clause,46  it  is  the  responsibility  of
                      Congress,  not this  Court,  to  amend the
                      statute  if Congress  deems it  unfair  or
                      unduly strict.
                                          IV
                           On  the premise  that the  purpose of
                      the mens  rea requirement is to avoid pun-
                      ishing  people   for  apparently  innocent
                      activity,    JUSTICE   GINSBURG  concludes
                      that  proof of knowledge  that a weapon is
                       `a dangerous device  of a type as  would
                      alert  one  to the  likelihood of  regula-
                      tion'   is  not  an  adequate  mens   rea
                      requirement,  but that  proof of knowledge
                      that the  weapon possesses   `every  last
                      characteristic'  that subjects it to reg-
                      ulation  is.    Ante,  at  3 5,  and  n. 5


                                          
                      hand grenade, the  possessor  of an  unfa-
                      miliar  object  such  as  a  hand  grenade
                      would  not know  that it was   a dangerous
                      item of  a type  likely to  be subject  to
                      regulation,  Brief  for United States  16;
                      see also  id., at  20, 23,  24, unless  he
                      knew what it was.
                         46Petitioner  makes no  such  claim in
                      this Court.










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      (GINSBURG,  J.,  concurring  in  judgment)
                      (quoting the  trial court's jury  instruc-
                      tion).
                           Assuming   that   innocent  activity 
                      describes conduct  without any  conscious-
                      ness  of wrongdoing, the risk of punishing
                      such  activity  can  be  avoided  only  by
                      reading  into the  statute the  common-law
                      concept  of mens rea:  an  evil purpose or
                      mental  culpability.     Morissette,   342
                      U. S. at 252.47  But even  petitioner does
                      not  contend  that  the  Government   must
                      prove   guilty   intent   or   intentional
                      wrongdoing.   Instead, the  mens rea   is-

                                          
                         47Our use of the term mens rea has not
                      been consistent.  In  Morissette, we  used
                      the  term as if it always  connoted a form
                      of  wrongful intent.   In other  cases, we
                      employ it  simply to  mean whatever  level
                      of knowledge is required for  any particu-
                      lar crime.   See, e.g.,  United States  v.
                      Bailey,  444 U. S.  394,  403 (1980).   In
                      this  sense,  every crime  except  a  true
                      strict liability  offense contains a  mens
                      rea requirement.   For instance, the Court
                      defined  mens rea  in Liparota  v.  United
                      States,  471  U. S.  419,  426 (1985),  as
                       knowledge  of illegality.    In  dissent,
                      however,  JUSTICE WHITE  equated the  term
                      with knowledge of the facts that  make the
                      conduct   illegal.     Id.,  at   442 443.
                      Today, the Court assigns the
                      term  the latter definition, ante, at 4 5,
                      but in  fact requires  proof of  knowledge
                      of only some of the facts  that constitute
                      the violation,  ante, at  8 9 (not requir-
                      ing proof  of knowledge of  the fact  that
                      the gun is unregistered).










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      sue in this case is simply what  knowledge
                      requirement, if  any, Congress  implicitly
                      included in  this offense.   There are  at
                      least  five such  possible  knowledge  re-
                      quirements, four of which entail  the risk
                      that  a completely  innocent mistake  will
                      subject a defendant to punishment.
                           First, a  defendant may know that  he
                      possesses  a weapon with all  of the char-
                      acteristics  that  make  it  a    firearm 
                      within  the  meaning of  the  statute  and
                      also know  that  it  has never  been  reg-
                      istered, but  be ignorant  of the  federal
                      registration  requirement.    In  such   a
                      case,  we  presume  knowledge  of the  law
                      even if we  know the  defendant is   inno-
                      cent  in  the sense that JUSTICE  GINSBURG
                      uses the  word.  Second,  a defendant  may
                      know that he  possesses a weapon  with all
                      of  the  characteristics  of  a  statutory
                      firearm  and   also  know   that  the  law
                      requires that it be  registered, but  mis-
                      takenly believe that it  is in fact regis-
                      tered.    Freed  squarely holds  that this
                      defendant's  innocence  is not a  defense.
                      Third, a defendant  may know only  that he
                      possesses a weapon  with all of the  char-
                      acteristics of a  statutory firearm.  Nei-
                      ther   ignorance   of   the   registration
                      requirement  nor  ignorance  of  the  fact
                      that the  weapon is unregistered  protects
                      this  innocent  defendant.  Fourth,  a de-
                      fendant  may  know  that  he  possesses  a
                      weapon that  is sufficiently dangerous  to
                      likely be regulated,  but not know that it
                      has  all the characteristics of a statuto-
                      ry firearm.   Petitioner  asserts that  he
                      is   an   example   of   this    innocent 
                      defendant.   Fifth, a  defendant may  know
                      that  he possesses  an  ordinary  gun and,










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      being aware of the  widespread lawful  gun
                      ownership in  the country, reasonably  as-
                      sume that  there  is no  need  to  inquire
                      about the need for  registration.    Ante,
                      at   3  (GINSBURG,   J.,   concurring   in
                      judgment).  That,  of course, is not  this
                      case.  See supra, at 1, and n. 1.48
                           JUSTICE  GINSBURG treats  the  first,
                      second, and third alternatives  different-
                      ly from the  fourth and fifth.  Her accep-
                      tance of knowledge of the  characteristics
                      of a  statutory  firearm   as a sufficient
                      predicate  for  criminal liability despite
                      ignorance of  either the duty to  register
                      or   the  fact   of  nonregistration,   or
                      both must rest  on the  premise that  such
                      knowledge  would alert  the owner  to  the
                      likelihood of regulation, thereby  depriv-
                      ing the conduct of  its  apparen[t]  inno-
                      cen[ce].   Yet in the  fourth alternative,
                      a  jury determines  just  such  knowledge:
                      that  the characteristics  of  the  weapon
                      known  to the  defendant would  alert  the
                      owner to the likelihood of regulation.
                           In    short,    JUSTICE    GINSBURG's
                      reliance on  the  purpose of the  mens rea
                      requirement to shield people against  pun-
                      ishment  for apparently  innocent  activi-
                      ty,  ante, at 3, neither explains why  ig-

                                          
                         48Although I disagree with the  assump-
                      tion   that     widespread   lawful    gun
                      ownership   provides  a  sufficient reason
                      for  believing that  there is  no  need to
                      register  guns (there  is also  widespread
                      lawful  automobile ownership),  acceptance
                      of that  assumption neither justifies  the
                      majority's  holding   nor  contradicts  my
                      conclusion on the facts of this case.










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      norance of certain facts is a defense  al-
                      though  ignorance of  others is  not,  nor
                      justifies   her  disagreement   with   the
                      jury's  finding that  this defendant  knew
                      facts that should  have caused him  to in-
                      quire about the need for registration.49
                                          V
                           This  case presents  no dispute about
                      the  dangerous  character  of  machineguns
                      and   sawed-off   shotguns.     Anyone  in
                      possession  of such  a weapon is  standing
                      in responsible relation  to a  public dan-
                      ger.   See  Dotterweich, 320 U. S., at 281
                      (citation   omitted).    In  the  National
                      Firearms  Act,  Congress  determined  that
                      the serious  threat to  health and  safety
                      posed  by  the private  ownership of  such


                                          
                         49In  addition,   contrary  to  JUSTICE
                      GINSBURG's  assumption, if  one reads  the
                      term   firearm  from the quoted section of
                      the indictment to  mean  gun,  the indict-
                      ment  still   charges  an  offense   under
                       5861(d)  and  does  not  differ from  the
                      critical jury instruction.   See ante,  at
                      3 4.  Even if
                      JUSTICE  GINSBURG is correct that there is
                      a technical variance, petitioner makes  no
                      claim  that any  such variance  prejudiced
                      him.   The wording of  the indictment,  of
                      course, sheds no light  on the proper  in-
                      terpretation of  the underlying  statutory
                      text.    Although the  repeated  use  of a
                      term in a  statute may shed  light on  the
                      statute's  construction,  see  Ratzlaf  v.
                      United  States, 510 U. S. ___ (1993) (slip
                      op.,  at 8), such use in  an indictment is
                      irrelevant to that question.










                                   92 1441 DISSENT

                               STAPLES v. UNITED STATES

                      firearms  warranted the  imposition  of  a
                      duty on  the owners  of dangerous  weapons
                      to determine  whether their possession  is
                      lawful.   Semiautomatic  weapons that  are
                      readily convertible  into machineguns  are
                      sufficiently  dangerous to  alert  persons
                      who knowingly possess them  to the  proba-
                      bility  of  stringent  public  regulation.
                      The jury's  finding that petitioner  know-
                      ingly possessed  a dangerous  device of  a
                      type as would alert one to  the likelihood
                      of  regulation   adequately  supports  the
                      conviction.

                           Accordingly,  I   would  affirm   the
                      judgment of the Court of Appeals.
