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New limits on ATF’s ability to expand statutory scope by redefining key terms may have broader implications.
In Garland v. Cargill, the U.S. Supreme Court held in a 6-3 decision that the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) exceeded its statutory authority in issuing a final rule that classified bump stocks as machine guns.
Assessment of this common-sense opinion must start with a review of the National Firearms Act, which defines a “machine gun” as “any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger.” The definition also includes “any part designed and intended solely and exclusively… for use in converting a weapon into a machine gun.”
In contrast to a machine gun, which can fire multiple shots when its trigger is engaged once, a semiautomatic firearm can fire only one shot per trigger engagement. There are shooting techniques, however, to increase the rate at which semiautomatic firearms can be fired.
One technique is “bump firing.” When bump firing, the shooter keeps his trigger finger stationary, while allowing the recoil energy from firing the gun to push the gun backward quickly and reset the trigger. Simultaneously, the shooter applies forward pressure on the gun with his non-trigger hand to “bump” the trigger into his still-stationary trigger finger, which fires a subsequent shot. When done effectively, bump firing allows semiautomatic firearms to fire at rates approaching machine guns.
A bump stock is a device that makes bump firing easier. Importantly, even with a bump stock, the Court noted that “as with any semiautomatic firearm, the trigger still must be released and reengaged to fire each additional shot.” Moreover, bump firing—with or without a bump stock—requires significant manual input from the shooter.
Reflecting these facts, in ten different letter rulings from 2008 to 2017, ATF concluded that bump stock-equipped rifles are not machine guns, for the simple reason they cannot “automatically” fire multiple shots “by a single function of the trigger.” In 2018, however, after the U.S. Congress declined to adopt legislation following a mass shooting in Las Vegas, ATF reversed course and promulgated a final rule classifying bump stocks as machine guns. The rule states that “the term ‘automatically’” in the NFA “means functioning as the result of a self-acting or self-regulating mechanism that allows the firing of multiple rounds through a single function of the trigger; and ‘single function of the trigger’ means a single pull of the trigger and analogous motions.” Furthermore, the ATF stated that the “term ‘machine gun’ includes a bump-stock-type device.”
Michael Cargill, a gun advocate and gun shop owner in Texas, challenged this rule, claiming that under the Administrative Procedure Act the ATF exceeded its authority because bump stocks are not “machine guns” under the statute. After an en banc U.S. Court of Appeals for the Fifth Circuit ruled in Cargill’s favor, the Supreme Court agreed to hear the case.
The Court applied common sense to the question presented and held that a bump stock-equipped semiautomatic rifle is not a machine gun.
First, the Court noted that a firearm equipped with a bump stock “does not fire more than one shot ‘by a single function of the trigger,’” because even with a bump stock, “a shooter must release and reset the trigger between every shot.” Indeed, as the majority opinion reasoned, “a bump stock merely reduces the amount of time that elapses between separate ‘functions’ of the trigger.”
Second, a bump stock-equipped rifle does not fire “automatically,” because “the shooter must do more than simply engage the trigger one time.” Specifically, the shooter must “actively maintain just the right amount of forward pressure on the rifle’s front grip with his non-trigger hand,” requiring the shooter to exert manual input.
The Court also rejected the government’s nontextual argument that bump stocks should be considered machine guns because, otherwise, machine-gun restrictions would be rendered ineffective since offenders could instead acquire bump stocks: “A law is not useless merely because it draws a line more narrowly than one of its conceivable statutory purposes might suggest,” the Court explained.
It further remarked that “it is difficult to understand how ATF can plausibly argue otherwise, given that its consistent position for almost a decade in numerous separate decisions was that” bump stocks are not machine guns.
By invalidating ATF’s final rule, the Court reinforced the fundamental principle that executive branch agencies cannot create laws; they may only enforce them. As Justice Samuel Alito explained in a concurring opinion, the statutory text of the NFA is clear, so any change to the law must come from Congress.
In addition to invalidating the final rule restricting bump stocks, the Cargill opinion is likely to have other far-reaching implications.
By making clear that ATF cannot simply rewrite statutory language it wishes was broader, Cargill casts doubt on other ATF rules. In recent years, ATF rules have redefined unfinished frames or receivers as firearms, redefined what constitutes a short-barreled rifle, and redefined what constitutes being “engaged in the business” of dealing in firearms. All these rules, like the rule re-classifying bump stocks as machine guns, not only change but contradict Congress’s clear statutory language. The Cargill decision, therefore, signifies that ATF exceeded its authority by enacting those rules as well.
In addition, both the majority and dissenting opinions in Cargill emphasized the difference between machine guns and semiautomatic firearms. Some lower courts have upheld prohibitions on certain semiautomatic firearms (repeatedly deemed “assault weapons”) by equating them with machine guns. Cargill, however, undermines this rationale by making clear that there are critical distinctions between such types of firearms.
Thus, while Cargill ensures that fundamental Second Amendment rights are not subject to the whims of unelected bureaucrats at ATF, the decision would appear to provide legal ammunition with which to challenge abuses of regulatory power by many other departments and agencies.
This essay is part of a series, titled The Supreme Court’s 2023-2024 Regulatory Term.