511 U.S. 600, 114 S. Ct. 1793, 128 L. Ed. 2d 608 (1994)
The National Firearms Act imposes strict registration requirements on statutorily defined firearms, including machineguns.1 A machinegun is defined 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.2 In 1986, Congress amended the Act to criminalize the mere possession of an unregistered machinegun, a violation punishable by up to ten years' imprisonment.3
In 1989, local police and Bureau of Alcohol, Tobacco and Firearms agents executed a search warrant at petitioner Steven Staples' home and recovered an AR-15 rifle.4 The AR-15 is the civilian version of the military's M-16 rifle and is manufactured with a metal stop on its receiver to prevent conversion to automatic fire.5 On Staples' rifle, however, the stop had been filed away, and the weapon had been assembled with an M-16 selector switch and several other M-16 internal parts, including a hammer, disconnector, and trigger.6 BATF agents tested the rifle and confirmed that it fired more than one shot with a single pull of the trigger.7 It was undisputed that the weapon was not registered as required by the statute.8
Staples maintained that the rifle had never been modified to fire automatically and that he had no knowledge that it was capable of doing so.9 At trial, he requested the District Court to instruct the jury that the Government must prove beyond a reasonable doubt that he knew the gun would fire fully automatically.10 The District Court rejected that request.11
Instead, it charged the jury that the Government need only prove the defendant knew he was dealing with a dangerous device of a type as would alert one to the likelihood of regulation.12 The jury returned a verdict of guilty, and the court sentenced Staples to five years' probation and a $5,000 fine.13 The Court of Appeals for the Tenth Circuit affirmed the conviction.14
The Supreme Court granted certiorari to resolve a conflict in the Courts of Appeals concerning the mens rea requirement under the statute.15
Whether the Government must prove that the defendant knew the weapon he possessed had the characteristics that brought it within the statutory definition of a machinegun?16
The language of the statute does not contain any express mens rea requirement.17 The common-law presumption against imposing strict liability is particularly apt in the case of a statute that is silent as to mens rea and that is used to punish otherwise lawful conduct.18 The Act is not a public welfare statute that regulates inherently dangerous items or activities.19 The items regulated by the Act are not dangerous in themselves.20 The statute's harsh penalties suggest that Congress did not intend to eliminate a mens rea requirement.21
Yes. The statute is silent concerning the mens rea required for a violation of section 5861(d).22 The common law generally required proof that the defendant knew the facts that made his conduct illegal.23 The items regulated by the Act are not dangerous in themselves, as an AR-15 rifle is not a dangerous weapon unless it is modified to fire automatically.24
The harsh penalties attached to violations of the Act further suggest that Congress did not intend to eliminate a mens rea requirement.25 Staples possessed what appeared to be a semiautomatic AR-15, a weapon with a long tradition of lawful ownership by private individuals.26 Staples claimed no knowledge of its automatic capability.27 The potential for criminalizing apparently innocent conduct without a knowledge requirement confirms that the Government must prove the defendant knew the characteristics that made the weapon a machinegun under the Act.28
The Government must prove that the defendant knew the weapon he possessed had the characteristics that brought it within the statutory definition of a machinegun.29
Related opinions on this issue
Joined by Justice O'connor
Justice Ginsburg concurs in the judgment.30 She agrees that conviction requires proof that the defendant knew he possessed a machinegun.31 The indictment charged knowing possession of a firearm.32
A firearm has a statutory definition that includes a machinegun.33 The jury instruction did not properly convey the knowledge of the characteristics.34 Only knowledge of the specific features that subject the weapon to regulation shields against punishment for apparently innocent activity.35
Widespread lawful gun ownership supports this conclusion.36
Joined by Justice Blackmun
Justice Stevens dissents.37 The statute is a public welfare statute regulating dangerous devices.38 The Government need only prove that the defendant knew he possessed a dangerous device of a type likely to be subject to regulation.39
The semiautomatic weapon was readily convertible into a machinegun.40 Such a weapon is sufficiently hazardous to place the possessor on notice.41 The majority's holding substitutes its policy views for Congress's judgment.42
The dissent would affirm the conviction based on the jury's finding.43