                 U.S. Supreme Court

 STAPLES v. UNITED STATES, 511 U.S. 600 (1994)

 HAROLD E. STAPLES, III, PETITIONER 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 machinegun 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
capability. 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 Page II 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 Page III 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. [ STAPLES v. UNITED
STATES, 511 U.S. 600 (1994) , 1] 

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 [
STAPLES v. UNITED STATES, 511 U.S. 600 (1994) , 2]  of the Act. 1 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 [ STAPLES v. UNITED STATES, 511 U.S. 600 (1994) ,
3]  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 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 [ STAPLES v. UNITED
STATES, 511 U.S. 600 (1994) , 4]  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 r