Supreme Court Upholds the Rule of Law by Rejecting the Trump Administration's Bump Stock Ban

Six justices agreed that federal regulators had misconstrued the statutory definition of a machine gun.

The U.S. Supreme Court today ruled that the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) exceeded its statutory authority when it purported to ban bump stocks by classifying them as machine guns. Although the Court's decision in Garland v. Cargill does not involve the Second Amendment, it upholds the rule of law and the separation of powers by striking a blow against bureaucratic attempts to impose new gun controls without congressional approval. The bump stock ban is one of several such attempts, two of which faced judicial setbacks shortly before the Supreme Court's bump stock ruling.

"This decision helps [rein] in an out-of-control federal government that has no respect for the People of the United States or our rights," said Brandon Combs, president of the Firearms Policy Coalition (FPC). "The President cannot change the law to fit his policy preferences."

The products targeted by the ATF rule that the Supreme Court rejected are designed to assist bump firing, which involves pushing a rifle forward to activate the trigger by bumping it against a stationary finger, then allowing recoil energy to push the rifle backward, which resets the trigger. As long as the shooter maintains the requisite amount of forward pressure and keeps his finger in place, the rifle will fire repeatedly. The "interpretive rule" at issue in this case, which was published in December 2018 and took effect three months later, banned stock replacements that facilitate this technique by allowing the rifle's receiver to slide back and forth.

The National Firearms Act of 1934 "defines a 'machinegun' as any weapon capable of firing 'automatically more than one shot…by a single function of the trigger,'" Justice Clarence Thomas notes in the majority opinion, which was joined by five of his colleagues. The definition also covers parts that are "designed and intended…for use in converting a weapon" into a machine gun. "We hold that a semiautomatic rifle equipped with a bump stock is not a 'machinegun' because it cannot fire more than one shot 'by a single function of the trigger,'" Thomas writes. And "even if it could, it would not do so 'automatically.' ATF therefore exceeded its statutory authority by issuing a Rule that classifies bump stocks as machineguns."

For nearly a decade, the ATF "took the position that semiautomatic rifles equipped with bump stocks were not machineguns under the statute," Thomas notes. "On more than 10 separate occasions over several administrations, ATF consistently concluded that rifles equipped with bump stocks cannot 'automatically' fire more than one shot 'by a single function of the trigger.'" The dissenting opinion by Justice Sonia Sotomayor, which was joined by Justices Elena Kagan and Kentaji Brown Jackson, glides over this illuminating history, which it mentions only in a footnote.

The ATF "abruptly reversed course," Thomas notes, after a gunman used rifles equipped with bump stocks to kill 58 people at a Las Vegas music festival in October 2017. That horrifying crime inspired several bills that would have banned bump stocks. But President Donald Trump, who maintained that new legislation was unnecessary, instructed the ATF to impose a ban by administrative fiat. Because that approach contradicted the statutory definition of "machinegun" and the ATF's longstanding interpretation of it, supporters of a legislative ban warned, it would inspire court challenges that were apt to succeed.

Because "the ATF lacks authority under the law to ban bump-fire stocks," Sen. Dianne Feinstein (D–California) said, "legislation is the only answer." Noting that "the law has not changed," Feinstein warned that "the gun lobby and manufacturers will have a field day" with the ATF's "about face," which relied partly on "a dubious analysis claiming that bumping the trigger is not the same as pulling it."

Feinstein was right. After surrendering two bump stocks to the ATF under protest, Texas gun shop owner Michael Cargill filed a lawsuit challenging the rule in the U.S. District Court for the Western District of Texas. Although a federal judge and a three-judge panel of the U.S. Court of Appeals for the 5th Circuit upheld the rule, the appeals court reversed those rulings in an en banc decision last year.

"A plain reading of the statutory language, paired with close consideration of the mechanics of a semi-automatic firearm, reveals that a bump stock is excluded from the technical definition of 'machinegun' set forth in the Gun Control Act and National Firearms Act," Judge Jennifer Walker Elrod wrote in the majority opinion. And even if that were not true, Elrod said, "the rule of lenity," which requires construing an ambiguous criminal statute in a defendant's favor, would preclude the government from punishing people for owning bump stocks.

That decision clashed with a 2022 ruling in which the U.S. Court of Appeals for the D.C. Circuit concluded that the ATF had followed "the best interpretation of the statute." By contrast, a plurality of eight 5th Circuit judges agreed that the ATF had violated the plain meaning of the statute. In resolving that circuit split, the Supreme Court endorsed the latter view.

During oral arguments in February, Principal Deputy Solicitor General Brian H. Fletcher conceded that "an expert" can bump-fire a rifle "without any assistive device at all" and that "you can also do it if you have a lot of expertise by hooking your finger into a belt loop or using a rubber band or something else like that to hold your finger in place." Dodging the logical implication that all semiautomatic rifles are machine guns, the ATF maintained that the additional assistance offered by bump stocks made a crucial difference.

One problem with the ATF's position was that semiautomatic rifles by definition fire just one round for each "function of the trigger." With or without a bump stock, the trigger has to be released and reactivated to fire additional rounds. In trying to get around that basic fact, Thomas notes, the ATF relied on "the mistaken premise that there is a difference between a shooter flexing his finger to pull the trigger and a shooter pushing the firearm forward to bump the trigger against his stationary finger." It "call[ed] the shooter's initial trigger pull a 'function of the trigger' while ignoring the subsequent 'bumps' of the shooter's finger against the trigger before every additional shot."

The statute, however, "does not define a machinegun based on what type of human input engages the trigger—whether it be a pull, bump, or something else," Thomas writes. "Nor does it define a machinegun based on whether the shooter has assistance engaging the trigger. The statutory definition instead hinges on how many shots discharge when the shooter engages the trigger."

Illustrating the problems with the ATF's workaround, the agency's reasoning contradicted itself. The rule "defines 'function of the trigger' to include not only 'a single pull of the trigger' but also any 'analogous motions,'" Thomas notes. "ATF concedes that one such analogous motion that qualifies as a single function of the trigger is 'sliding the rifle forward' to bump the trigger." If so, "every bump is a separate 'function of the trigger,"' and semiautomatic rifles equipped with bump stocks are therefore not machineguns."

The ATF claimed "a semiautomatic rifle equipped with a bump stock fires more than one shot by a single function of the trigger because a shooter 'need only pull the trigger and maintain forward pressure' to 'activate continuous fire,'" Thomas notes. "If that is correct, however, then the same should be true for a semiautomatic rifle without a bump stock. After all, as the dissent and ATF themselves acknowledge, a shooter manually bump firing a semiautomatic rifle can achieve continuous fire by holding his trigger finger stationary and maintaining forward pressure with his nontrigger hand." Yet "they agree that a semiautomatic rifle without a bump stock 'fires only one shot each time the shooter pulls the trigger,'" he adds. "Their argument is thus at odds with itself."

Another problem with the ATF rule was its definition of "automatically." The statute "specifies the precise action that must 'automatically' cause a weapon to fire 'more than one shot'—a 'single function of the trigger,'" Thomas writes. "If something more than a 'single function of the trigger' is required to fire multiple shots, the weapon does not satisfy the statutory definition."

Bump firing "requires more than a single function of the trigger," Thomas notes. "A shooter must also actively maintain just the right amount of forward pressure on the rifle's front grip with his nontrigger hand. Too much forward pressure and the rifle will not slide back far enough to release and reset the trigger, preventing the rifle from firing
another shot. Too little pressure and the trigger will not bump the shooter's trigger finger with sufficient force to fire another shot. Without this ongoing manual input, a semiautomatic rifle with a bump stock will not fire multiple shots."

The ATF tried to rebut that point by arguing that firing a machine gun also requires additional action: The shooter must keep the trigger depressed. But "simply pressing and holding the trigger down on a fully automatic rifle is not manual input in addition to a trigger's function—it is what causes the trigger to function in the first place," Thomas writes. "By contrast, pushing forward on the front grip of a semiautomatic rifle equipped with a bump stock is not part of functioning the trigger. After all, pushing on the front grip will not cause the weapon to fire unless the shooter also engages the trigger with his other hand. Thus, while a fully automatic rifle fires multiple rounds 'automatically…by a single function of the trigger,' a semiautomatic rifle equipped with a bump stock can achieve the same result only by a single function of the trigger and then some."

While all this arcane analysis might seem like nitpicking, it is exactly what a court must do in seeking to apply a statute as written. As Fletcher conceded, Congress did not define a machine gun by rate of fire. "This is not a rate-of-fire statute," he said. "It's a function statute." Although it may seem logical that any weapon that can approximate a machine gun's rate of fire should be placed in the same category, that is not the law Congress wrote.

"There can be little doubt that the Congress that enacted [this law] would not have seen any material difference between a machinegun and a semiautomatic rifle equipped with a bump stock," Justice Samuel Alito writes in a concurring opinion. "But the statutory text is clear, and we must follow it."

Although the Las Vegas mass shooting "demonstrated that a semiautomatic rifle with a bump stock can have the same lethal effect as a machinegun," Alito writes, "an event that highlights the need to amend a law does not itself change the law's meaning. There is a simple remedy for the disparate treatment of bump stocks and machineguns. Congress can amend the law—and perhaps would have done so already if ATF had stuck with its earlier interpretation. Now that the situation is clear, Congress can act."

Whatever the merits of a bump stock ban, in other words, regulators cannot rewrite the law to impose one, especially when that decision transforms gun owners who abided by the law as the ATF had repeatedly explained it into felons overnight. Similar bureaucratic reversals concerning pistol braces, homemade guns, and the definition of firearm dealers raise the same basic problem.

Yesterday a federal judge in Texas vacated an ATF rule that redefined pistols with braces as short-barreled rifles under the National Firearms Act. U.S. District Judge Reed O'Connor described the rule as "unlawful" and "illegitimate." The ATF under the Biden administration "hates us so much that it lawlessly acted to turn millions of gun owners into felons," the FPC's Combs said, "but FPC and our members ran towards the fire and defeated this evil."

In another Texas case this week, a federal judge temporarily blocked an ATF rule that sought to expand background checks for gun buyers by requiring that anyone who sells guns to "predominantly earn a profit" obtain a dealer license. U.S. District Judge Matthew Kacsmaryk concluded that the plaintiffs were "substantially likely to succeed on the merits" of their claim that ATF had misconstrued the statutory definition of "engaged in the business" of selling firearms.

All of these cases raise an issue that goes far beyond the particulars of gun regulation. Due process, the rule of law, and the separation of powers preclude the executive branch from inventing new crimes by twisting the meaning of statutes in response to political pressure.