Can Congress Ban Bump Stocks?

In the wake of the horrific mass shooting in Las Vegas, initial reactions from lawmakers followed a familiar pattern. Democrats (and others) who support stricter gun control pointed to the killer’s easy access to firearms, while Republicans (and others) who oppose stricter gun control objected that it would be inappropriate to use the tragedy for political ends. That response in turn led gun control advocates to ask rhetorically, as they have in the past, when would be the right time to talk about gun control. A sense of déjà vu prevailed.

Yet after authorities determined that shooter Stephen Paddock had used “bump stocks”—devices that reflect the recoil from a semi-automatic rifle against the shooter’s shoulder back into his trigger finger in order to simulate the action of a fully automatic rifle—the debate took a surprising turn. Long-time opponents of stricter gun control indicated an openness to new legislation banning bump stocks. Even the National Rifle Association suggested that it would accept executive action (though not new legislation) to regulate bump stocks.

It remains possible that no action will be taken to ban or further regulate bump stocks, but even the suggestion of bipartisan support for any sort of gun control is unusual. What accounts for it?

The short answer is that federal law already forbids the transfer or possession of most machineguns and parts to convert legal semi-automatic weapons into machineguns. Thus, forbidding bump stocks may be seen as simply closing a loophole in the existing gun control regime rather than expanding that regime.

Yet that answer is not fully satisfactory. People and groups favoring gun rights have long opposed closing other loopholes—like the provision that allows the purchase of a firearm at a gun show without the same background check that would be required to purchase firearms from a regular store. What’s different about the bump stock loophole? Gun rights advocates invoke the Second Amendment to oppose all other sorts of gun control measures. Why do they accept a ban on fully automatic weapons?

As a constitutional lawyer, I am not especially qualified to answer a question about the psychology of gun rights activists. However, I can shed some light on a related question: Does the Second Amendment protect fully automatic rifles—and thus bump stocks? The answer is no, at least for now, but as I explain below, that might change if Congress does not act quickly.

The Heller Decision

For many years, the courts regarded the Second Amendment as posing virtually no obstacle to substantial regulation of firearms. Because its text identifies the maintenance of a “well regulated Militia” as the provision’s focus, the Amendment was understood by many to protect a collective right that could only be exercised within the context of military service.

That changed in 2008 when the Supreme Court, in an opinion by Justice Scalia in District of Columbia v. Heller, ruled that the Second Amendment protects a right of individuals to possess firearms in their homes for their personal use for self-defense. According to the Heller Court, at the time of the Founding, able-bodied (white) men would keep arms in their homes for self-defense and other purposes, and they would thus have arms available for collective defense of the community or state if called upon.

The Heller case involved a challenge to a D.C. law limiting possession of handguns. It did not address laws restricting other kinds of firearms. However, one might think that if the purpose of the individual Second Amendment right to possess firearms was to ensure that militiamen would have arms when called to muster, then the individual right would include whatever personal arms might be useful in military service. Today, that would include fully automatic weapons. Indeed, during the oral argument in the Heller case, Solicitor General Paul Clement noted that machineguns are “the standard issue armament for the National Guard.”

During that same argument, former Solicitor General Walter Dellinger, representing the District of Columbia, pressed the point further: Finding an individual Second Amendment right would result in invalidation of the machinegun ban, he contended, and therefore the Court ought not find such a right.

Justice Scalia pushed back. Foreshadowing what he would eventually write in his opinion for the Court, he said that the Second Amendment only protects weapons in “common use.” And in the opinion he suggested that Congress may ban machineguns, what he called “M-16 rifles and the like.”

Still, the Heller case involved handguns, not machineguns, and even the dicta about machineguns was at best a hint, rather than a clear statement that Congress can ban machineguns. The actual test the Court announced for whether weapons count as “arms” protected by the Second Amendment is whether they are in “common use,” as opposed to “dangerous and unusual weapons.”

Are Machineguns in “Common Use”?

That last phrase is conjunctive. In order to be excluded from the “arms” protected by the Second Amendment, a weapon apparently must be both dangerous and unusual. We can stipulate that machineguns are especially dangerous, but are they unusual? Not really.

The federal machinegun ban is not total. For instance, it exempts machineguns lawfully possessed prior to 1976. During the Heller argument, Clement said that there were 160,000 privately possessed machineguns and that this amounted to “common use.” It turns out that Clement’s figure was an understatement. In response to a Freedom of Information Act request, in 2016 the Bureau of Alcohol, Tobacco, Firearms and Explosives revealed that there are actually just shy of half a million machineguns registered in the National Firearms Registration Transfer Record System. Adding in unregistered machineguns would bring the number even higher.

Thus, there may already be so many privately owned machineguns as to call into question the constitutionality of the federal restrictions on their possession or transfer.

“Common use” and “unusual” are vague terms. Nonetheless, in evaluating a post-Heller challenge to another District of Columbia gun control law—and also featuring Mr. Heller as the lead plaintiff—the US Court of Appeals for the District of Columbia had little difficulty concluding that semi-automatic rifles subject to the District’s assault rifle ban are in common use, noting that between 1986 and 2011 (when the case was decided) roughly 1.6 million AR-15s (the most popular semiautomatic rifle) were sold. There clearly are fewer privately owned machineguns than privately owned semiautomatic rifles, but private ownership of machineguns appears to be roughly within an order of magnitude of private ownership of semiautomatic rifles. Although one could quibble about where exactly the threshold should be set, judging by the numbers it appears that machineguns are in common use.

Can Congress Regulate Nonetheless?

To say that machineguns are in common use and thus “arms” within the meaning of the Second Amendment does not necessarily mean that they cannot be banned. In the 2011 DC Circuit case, the court found that semiautomatic rifles are “arms” but that the law banning them was valid because of the great danger to public safety that semiautomatic weapons present. In so ruling, the court first found that laws restricting Second Amendment rights should be subject to intermediate scrutiny—which, as the term suggests, is not so stringent a test as the “strict” scrutiny that applies to laws directed at First Amendment rights but not so lenient a test as the “rational basis” review that applies to laws that do not implicate any special right.

Yet not everyone agrees that intermediate scrutiny is the right standard to apply to firearms regulations. For example, in a 2016 decision, a panel of the US Court of Appeals for the Fourth Circuit held that strict scrutiny should apply to laws that burden the “use of a class of arms for self-defense in the home.” The panel applied that test to invalidate Maryland’s ban on most semiautomatic rifles.

That ruling was displaced by an en banc decision of the Fourth Circuit earlier this year. The en banc court first concluded that semiautomatic weapons are not arms within the meaning of the Second Amendment because, regardless of their numbers, they are very similar to fully automatic weapons, which, the en banc court reasoned, had been excluded from the Second Amendment’s coverage by the Supreme Court’s statement in Heller. The en banc court next concluded that even if semiautomatic rifles were protected, the Maryland law restricting them would be justified under intermediate scrutiny, which, the en banc court said, applies. The plaintiffs have sought review by the Supreme Court.

Meanwhile, in the 2011 DC Circuit case itself, Judge Kavanaugh argued in dissent that neither strict nor intermediate scrutiny should apply. Instead, Judge Kavanaugh read the Supreme Court’s Heller decision and its 2010 decision in McDonald v. City of Chicago to command that courts should “assess gun bans and regulations based on text, history, and tradition.” He then concluded that the District’s ban on semiautomatic weapons was invalid. Like the en banc Fourth Circuit, Judge Kavanaugh relied on a comparison, but a different one. Heller, he said, invalidated a ban on handguns, including semiautomatic handguns, and, in his view, there were no salient differences between semiautomatic handguns and semiautomatic rifles.

Whether one sides with the Fourth Circuit en banc court or Judge Kavanaugh thus depends partly on whether one thinks a semiautomatic rifle is more like a fully automatic rifle or more like a semiautomatic handgun. This is a bit like asking whether a bat is more like a crow because they both can fly or more like a dolphin because they both can echolocate.

Congress Should Act Quickly

No doubt the Supreme Court will eventually need to clarify both how to determine whether a type of weapon counts as an “arm” under the Second Amendment and, if it does, how to assess the validity of a regulation of that type of weapon. In the meantime, if Congress wishes to regulate bump stocks, it should move quickly to do so.

Although the validity of the federal machinegun ban might not turn on the number of machineguns in circulation, it might. After all, one plausible definition of “common use” depends on numbers.

Luckily, so far as the machinegun ban itself is concerned, there is no urgency. Because new machineguns have been banned from the market for over four decades, their number is stable.

Bump stocks are a different story, however. So long as bump stocks remain legal, people who wish to circumvent the machinegun ban can, as it were, stock up on them. If enough people do that before Congress (or the president via executive action) bans bump stocks, there could be so many in circulation as to qualify as in common use.

To be sure, as both the DC Circuit and the en banc Fourth Circuit concluded with respect to semiautomatic rifles, even if a type of weapon is in common use, it may not be fully protected by the Second Amendment. But with the constitutional law in this area in a state of uncertainty and flux, the prudent course for Congress to take would be to act quickly so as to foreclose the common use opening.

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