The U.S. Supreme Court’s 2008 decision in District of Columbia v. Heller ushered in a new era in Second Amendment jurisprudence, holding that the constitutional right “to keep and bear arms” meant an individual right independent of service in an organized militia. The decision reignited the country’s debate over gun control, in which gun-control advocates have asserted that the Second Amendment’s drafters did not anticipate the lethality of present-day technology and would not have endorsed the private ownership of certain modern firearms.
The Court rejected the first part of this argument as “bordering on the frivolous,” noting that, just as the First Amendment applies to modern forms of communication, the Second Amendment applies “to all instruments that constitute bearable arms, even if not in existence at the time of the founding.” But the Court clarified that this did not mean that the right to bear arms extended to any type of weapon whatsoever, and that for some types, restrictions or even prohibitions would be proper.
But if newness is not the criterion to distinguish technologies protected by the Second Amendment from those that are not, what is? This is not merely an academic question, as courts in Heller’s wake have been bombarded with Second Amendment challenges covering all manner of weapons, from machine guns and assault rifles, to high-tech but non-lethal alternatives such as TASERs and stun guns, to thoroughly pre-modern weapons like knives and clubs. As the challengers have noted, if the right to bear arms truly is independent of militia service, there is no reason to limit the right to weapons intended for military use. Unsurprisingly, the scope of the constitutional right to bear arms has yet to be worked out and will likely remain uncertain for so long as both weapons and the laws governing them continue to evolve.
Until Heller, Second Amendment case law was anchored in the amendment’s prefatory clause, which states, “A well regulated Militia, being necessary to the security of a free state . . . .” Based on that clause, lawyers and judges understood the amendment to protect the right of states to keep armed militias independent of the federal army, not the right of private citizens to keep arms for self-defense. Consistent with that understanding, the Supreme Court held in United States v. Miller (1939) that a federal law against the interstate transport of sawed-off shotguns did not offend the Constitution because such weapons were not used for militia purposes. Although the decision never stated that membership in a militia was the touchstone of the right to bear arms, that is how it was interpreted for decades thereafter, with the result that challenges to gun restrictions were few and far between.
Against this backdrop, the Heller decision was a watershed event. There, the Supreme Court struck down a D.C. statute banning the possession of handguns, holding that citizens had the right to keep a gun for self-defense. In so holding, the Court did not overrule Miller but explained that the case turned on the fact that it involved sawed-off shotguns, which—in addition to having no military use—were not “in common use” by law-abiding citizens, and thus could be subject to restriction. In contrast, the Court explained, a handgun like the one Mr. Heller owned was the nation’s “most preferred firearm” for home defense and, thus, protected by the Constitution. Although the statute challenged in Heller was a federal one—the District of Columbia being outside the jurisdiction of any state—subsequent cases have held Heller applicable to states and localities as well, with the result that analogous handgun laws in cities around the United States have been held unenforceable.
Since Heller, courts have had to apply its logic to other types of weapons, requiring them to consider what it means to be in “common use,” as well as whether a weapon’s suitability for military purposes is still relevant to its Second Amendment status. One relatively straightforward case has been the machine gun, the federal umbrella term for all firearms capable of firing multiple rounds with a single press of the trigger. Citing Heller, multiple plaintiffs have challenged the federal law prohibiting the private ownership of machine guns, arguing that the right to bear arms must at minimum cover weapons that are militarily useful, as any other conclusion would read the clause about “a well-regulated Militia” out of existence. Courts have uniformly rejected this argument, however, noting that machine guns have never been in “common use,” which—more so than military effectiveness—was the key characteristic of weapons kept by a citizen militia.
Far more challenging than the machine gun has been its civilian counterpart, the semi-automatic assault rifle. Unlike a machine gun, an assault rifle fires only one round per trigger press, but because its firing mechanism automatically chambers the next round—hence the name, “semi-automatic”—it is capable of a far higher rate of fire than a standard rifle. Also unlike machine guns, assault rifles are not illegal under federal law or the laws of most states, and, indeed, they are among the most popular privately owned firearms in the United States.
Given that such weapons are both in “common use” and effective for military use—they are modeled on military rifles, lacking only the capability for fully automatic fire—one might think they present an obvious instance of a militia weapon covered by the Second Amendment. But that would be wrong: In states with laws restricting assault rifles, courts have upheld those laws against constitutional challenges, with one court concluding that assault rifles fell outside the Second Amendment specifically because of their military effectiveness, holding them to be “weapons of war” rather than arms intended for self-defense.
Given that a weapon’s suitability for military purposes now appears to count against constitutional protection, it is perhaps unsurprising that less lethal arms have fared better in the courts. Eight years after Heller, the Supreme Court struck down a Massachusetts statute barring the possession of electric stun guns, rejecting the lower court’s reasoning that such weapons fell outside the Second Amendment because they were not “readily adaptable to use in the military.” As Justice Alito noted in concurrence, stun guns provide effective non-lethal self-defense, and it would be highly undesirable to put citizens to the Hobson’s choice of either carrying a lethal firearm or simply going unarmed. Police batons, billy clubs, and knives have also been deemed protected by the Second Amendment, for the similar reason that, whatever their utility to a modern army, they are well-established weapons of self-defense.
Technology evolves as knowledge improves, and weapons are no exception. The newest front in the ongoing battle between gun owners and regulators concerns the “bump stock,” an adaptation that, using an assault rifle’s natural recoil, causes the weapon to bounce forward off the shooter’s shoulder and against his trigger finger, enabling a semi-automatic firearm to fire at a rate near that of a machine gun. In recent years, the ATF has issued regulations stating that bump-stock-equipped rifles are machine guns and, therefore, prohibited by federal law.
Whether this is correct as a matter of statutory construction is presently before the Supreme Court in Garland v. Cargill. While that case does not formally present a constitutional challenge, it would be foolish to think that the Second Amendment will not factor in the justices’ decision. Should the Supreme Court determine that bump stocks are machine guns—and, therefore, prohibited—it will have held that a popular form of firearm already in citizens’ hands may not be improved to keep pace with technology. If past is prologue, such an outcome seems unlikely.
