Supreme Court ruling against ATF's bump stock ban leaves it up to Congress

Last week in Garland v. Cargill the Supreme Court struck down the Bureau of Alcohol, Tobacco, Firearms, and Explosives’ interpretive regulation that banned the possession of bump stocks by classifying them as machineguns under federal law. Given the subject matter of the case, it is worth noting at the outset that this is not a Second Amendment case; rather, it is a case about the authority of the executive branch (and its agencies) and statutory interpretation.

The lay of the land

Congress enacted the National Firearms Act in 1934 in response to the proliferation of firearms (like machineguns and “sawed-off” guns) favored by organized crime. (Think Al Capone and Pretty Boy Floyd and Tommy Guns.) Through the NFA and subsequent legislation passed in 1968 and 1986, federal law now generally bans the transfer or possession of machineguns, including devices that can be used to convert a weapon into a machinegun. The dispute in Cargill turns on the NFA’s statutory classification of “machinegun,” which it defines as any weapon that can fire “automatically more than one shot … by a single function of the trigger.”

It is helpful to understand the basic difference between machineguns (which are banned under federal law) and semiautomatic weapons (which are not). In simple terms: A semiautomatic firearm automatically loads a cartridge into the chamber after firing, and the shooter then must pull the trigger again to fire (one pull of the trigger, one bullet). A machinegun, by contrast, will fire more than one shot when the shooter holds down the trigger (one pull of the trigger, more than one bullet). The usual examples here are an M-16 (a machinegun capable of automatic fire) and an AR-15 (a semiautomatic rifle that fires only one round for each pull of the trigger).

So what is a bump stock? It’s an accessory that attaches to a semiautomatic rifle and allows for “bump firing,” a firing technique where a shooter relies on the firearm’s recoil to reengage the trigger and increase the rate of fire. These devices became the focus of national attention after the October 2017 mass shooting in Las Vegas, where the gunman had equipped some of his firearms with bump stocks. While the shooting spurred several Congressional proposals to ban bump stocks, none of those bills became law.

Enter the ATF. For over a decade, ATF had issued interpretative guidance and classification letters consistently stating that non-mechanical bump stocks fall outside the statutory definition of “machinegun.” After the Las Vegas shooting, however, the agency reversed course and in 2018—during the Trump Administration—adopted a final rule that defined “machinegun” to include a “bump-stock device.” The ATF rescinded its previous regulatory guidance concluding that bump stocks were not machineguns, and instructed owners to destroy their devices or surrender them to the ATF. Based on the ATF’s estimates, there were upwards of 520,000 bump-stock devices in circulation at the time of the rulemaking.

Cargill’s case

After ATF adopted the final rule, Michael Cargill surrendered two bump-stock devices to the agency and sued in the Western District of Texas. The district court ruled in the government’s favor and a Fifth Circuit panel affirmed, but the en banc court reversed.

The Supreme Court granted certiorari to decide whether a semiautomatic rifle equipped with a bump stock is a “machinegun.” In a 6-3 opinion by Justice Thomas (joined by Chief Justice Roberts and Justices Alito, Gorsuch, Kavanaugh, and Barrett), the court held that a bump-stock-equipped rifle does not meet the NFA’s definition because (1) “it cannot fire more than one shot ‘by a single function of the trigger,’” and (2) “even if it could, it would not do so ‘automatically.’” On the first point, the Court reviewed the mechanics of bump firing and concluded that a bump stock does not alter the fundamental mechanics of a semiautomatic rifle: For every shot, the shooter must allow the trigger to reset and then reengage the trigger for another shot. “Even with a bump stock, a semiautomatic rifle will fire only one shot for every ‘function of the trigger.’” On the second point, the Court explained that a bump stock does not allow a semiautomatic rifle to fire “automatically” because the shooter must take action beyond simply holding down the trigger—in the opinion’s terms, a shooter must provide “ongoing manual input” to fire multiple shots. In short, the ATF exceeded its statutory authority because the final rule’s definition of “machinegun” strays from the four corners of the statutory text.

Justice Alito wrote a three-paragraph concurring opinion, noting that while the current statutory language doomed ATF’s interpretation, “Congress can amend the law” to address the classification of bump stocks.

Justice Sotomayor, joined by Justices Kagan and Brown-Jackson, dissented. In their view, Congress’ choice of language “naturally covers” bump stocks because they enable a semiautomatic rifle to provide “continuous fire” through a single pull of the trigger “so long as the shooter maintains forward pressure on the gun.” In responding to the majority’s two primary points, the dissent (1) points to statutory language and context to argue that “single function of the trigger” refers to the shooter’s actions as opposed to the gun’s firing mechanism; and (2) that the use of a bump stock “automates the process of firing more than one shot” such that it enables a semiautomatic firearm to fire “automatically.”

Key takeaways

So where does that leave us? A few observations:

First, what’s next for bump stocks. Some states already have laws regulating bump stocks or banning them outright, and the Court’s decision has spurred renewed calls for congressional action. With the ATF’s rule out of the way, expect Second Amendment challenges to both these state laws and any federal ban (should one pass).

Second, this is a reminder of the centrality of statutory language in cases challenging agency action. Litigators of all stripes should heed this textual approach since it is perhaps the only piece of common ground among all nine justices in Cargill. And this may well be a preview of the Court’s work next term in Garland v. VanDerStok, another challenge to ATF’s regulatory efforts (that case concerns the statutory definition of “firearm” as it relates to a “frame or receiver”).

Finally, Cargill is consistent with the Court’s efforts to police separation-of-powers boundaries. This is a key theme of the term, and we will surely see more in this vein when the Court issues decisions in Loper Bright Enterprises v. Raimondo and Relentless, Inc. v. Department of Commerce. It’ll be an interesting few weeks.