Garland v. Cargill (on Bump Stocks) Explained

Why did the Supreme Court reverse the federal ban on bump stocks? Professor Joseph Blocher of Duke Law School provides an in-depth legal analysis.

The recent Supreme Court decision in Garland v. Cargill overturned the ATF's ban on bump stocks, a device that enables semi-automatic firearms to fire at rates similar to automatic weapons by using the recoil energy to reset the trigger. Professor Blocher highlights that the controversy stems from the interpretation of federal law defining machineguns. The law states that machineguns are weapons that fire multiple rounds with “a single function of the trigger.” The ATF argued that bump stocks effectively create a single trigger function, but the Supreme Court disagreed. The Court's decision, authored by Justice Thomas, emphasized the technical mechanism of the trigger resetting with each shot, thus not fitting the statutory definition of a machine gun.

The discussion also delves into the implications of this decision for future gun regulations. Professor Blocher notes that the ruling does not preclude Congress from enacting new legislation to ban bump stocks explicitly. However, the decision underscores the limitations of executive agencies in interpreting existing laws beyond their clear text. Professor Blocher also touches on related legal questions, such as the regulation of gun parts kits and the broader implications for firearms law. 

Joseph Blocher is a Professor of Law at Duke Law School and co-director of the Duke Center for Firearms Law.

Additional Resources

This video was created in collaboration with the Duke Center for Firearms Law, dedicated to the development of firearms law as a scholarly field through the support of reliable, original, and insightful scholarship, research, and programming.

  • National Firearms Act of 1934, 26 U.S.C. §5845(b): Defines "machinegun." 

    The term “machinegun” means 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 term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts designed and intended, for use in converting a weapon into a machinegun, and any combination of parts from which a machinegun can be assembled if such parts are in the possession or under the control of a person.

Garland v. Cargill (on Bump Stocks) Explained  Brief Transcript

Joel Cohen (Host): Hello and welcome to TalksOnLaw. I'm Joel Cohen. Today we're talking about a recent Supreme Court decision that just came down overturning the ban on bump stocks. We have a Second Amendment scholar and a Talks on Law favorite with us. Professor Joseph Blocher teaches at Duke Law School and is the co-director of the Duke Center for Firearms Law. Joseph, welcome back to Talks on Law.

Professor Joseph Blocher: Thanks so much for having me, Joel. It's good to see you.

Host: It is always a pleasure. This case, you and I had spoken about Rahimi. This was the domestic violence case. I've been following some other Second Amendment cases. I wasn't even aware that this bump stock case was pending.

Professor Joseph Blocher: Yeah, I mean, and maybe rightly so because it's technically not a Second Amendment case. It's sort of been reported as having been a big, you know, maybe big win for gun rights, and I don't think that's exactly right. It's a case about statutory interpretation and about what has been prohibited under existing law, not what could be prohibited consistent with the Second Amendment. So it's really like, in some ways, a very narrow debate about just what a couple of words in a single statute mean and whether the ATF's interpretation of those words is permissible.

Host: I think for most of us, except perhaps a small subset of gun enthusiasts, we were introduced to the word bump stock after the Las Vegas shooting. Maybe you can explain what a bump stock is and I suppose how and when it was banned.

Professor Joseph Blocher: Yeah, and actually the fact that this entered your consciousness around the time of the Las Vegas shooting, that again, probably no accident. That's when the rule that's at issue here was enacted. That was in 2018 when it was enacted. In fact, just worth noting, it was during the Trump administration. There was sort of a broad, at least at the moment, bipartisan support for banning these things. So what bump stocks are is a method of making semi-automatic weapons fire more quickly. A semi-automatic weapon is one where with each function of the trigger or each pull of the trigger, and that ends up becoming a very important distinction here, one bullet is fired, right? So the trigger has to pop back and forth every time you use it, every time you want to fire a bullet. That's different from what is traditionally considered an automatic weapon where if you just hold the trigger down, bullets will continue to fire. So when people think about machine guns, for example, that's usually what they have in mind. You hold down the trigger, it continues to shoot bullets. Semi-automatic, the trigger has to be pulled repeatedly. What bump stocks do essentially is convert the energy of the recoil from the weapon, the semi-automatic weapon, when it's fired to bump the weapon forward so that the trigger gets bumped against the finger of the shooter repeatedly. And the more quickly it happens, the more quickly it shoots. So a well-functioning bump stock, if the person who's holding the gun keeps their finger in place and maintains the right amount of forward pressure, can shoot 400 to 800 times a minute.

Host: 400 to 800 times a minute? I didn't even think automatic weapons could fire that quickly.

Professor Joseph Blocher: Yeah, apparently they can fire a thousand times a minute now. That's what my understanding from reading the record is pretty extraordinary. So you can understand why there might be some push to try to regulate them, especially when they're used in a high-profile incident like that one. But there was no direct law speaking exactly to bump stocks or using the phrase bump stock. Instead, what we have is a federal law which highly regulates machine guns. Machine guns are defined under the federal statute as a weapon that automatically fires without manual reload more than one bullet with a single function of the trigger. That phrase "single function of the trigger" is really the center of this case. So in the wake of the Las Vegas shooting, ATF passed a regulation saying we're going to treat bump stocks like machine guns because they effectively fire multiple shots with a single function of the trigger. There doesn't seem to be much disagreement that a weapon that is outfitted with a bump stock operates like a machine gun. And in fact, in a really remarkable concurring opinion in this case, Justice Alito says that exactly. He says the Congress that enacted this rule about machine guns undoubtedly would have seen no difference between a machine gun and a semi-automatic outfitted with a bump stock because they operate in, for all intents and purposes, almost the same.

Host: But interestingly, he still found with the majority..

Professor Joseph Blocher: Yes, that's right. Because the challenge here is not whether that's constitutional, whether it's okay to prohibit bump stocks or machine guns or any of that. There's explicitly this is not a Second Amendment case. What it's about is is the ATF's interpretation of that statute permissible. So the statute again refers to guns that fire multiple bullets with a single function of the trigger. ATF says, well, bump stocks do that. The majority, and this is a 6-3 decision here, the majority, in an opinion by Justice Thomas, says the ATF's interpretation here is not permissible because the function, like the actual firing mechanism of the weapon, requires the trigger to be reset each time, right? So even if it is bumping very, very quickly, the trigger is functioning repeatedly. So Justice Thomas says this is just the equivalent technologically of a person with a lightning-fast trigger finger. If you could physically do this 400 times in a minute, you would just be like a personal machine gun.

Host Joel Cohen: And that wouldn't make you subject to regulation under the federal law. They wouldn't have a right to take away your finger.

Professor Joseph Blocher: That's exactly right. They would have no right to limit your ability to do that, at least just the speed of it, right? So Justice Thomas says this is not a machine gun under this phrasing, right? A single function of the trigger.

Host Joel Cohen: I got to say, it sounds to me Justice Thomas's argument is very law professor-ish. It's interesting. It's very technical.

Professor Joseph Blocher: But in some ways, it's a technical case. And actually, interestingly, his opinion, you know, we law professors, it's just words, words, words, right? Justice Thomas has pictures. So in the opinion here, actually, he takes diagrams from an amicus brief filed in this case to really show how a trigger works and how it resets. His argument again is just the trigger has to reset each time. That means it's functioning multiple times, right? I mean, the way I think about it, he's looking at this question kind of from the perspective of the gun, right? From the gun's perspective, it has to reset each time. Now, Justice Sotomayor writes a dissenting opinion where she looks at things effectively from the perspective of the shooter, which is like you pull your finger once, as long as you hold it in place and maintain the right pressure on the weapon, it will continue to fire. And that's the function. There's a single function, and that initiates the firing sequence, which then, thanks to the bump stock, will continue on its own. And so if you like, that's the difference between the two opinions. One focusing on things from the perspective of the gun, the other focusing on things from the perspective of the shooter.

Host Joel Cohen: Interesting. It also seems like it was sort of arbitrary the way they defined automatic weapons. I mean, they could have defined automatic weapons based on the rate of bullets that could be shot, or they could have defined it in a different way, but they actually used the trigger in the definition.

Professor Joseph Blocher: Yeah, one of the things that's really interesting in gun cases, and this is actually true for a case that'll be argued in the fall of 2024, a case called Vanderstok, it's sometimes just hard to know what falls within the category. So Vanderstok is a case about whether gun parts kits are subject to the same regulations as guns. So for example, if you sell, if you're in the business of selling firearms, you have to do a background check when you sell that gun to make sure the person you're selling to isn't a felon. But if you're selling a kit which is, let's say, 80% finished and requires some pieces to be put together, you don't because it's technically not a gun. And so the question in Vanderstok really is, well, can the ATF regulate the gun parts kits the same way it regulates guns, right? Again, it's a definitional question. Like when does this become a gun?

Host Joel Cohen: Am I right that you could buy a kit and then maybe another couple parts and then you have a fully functioning gun?

Professor Joseph Blocher: You can go online and read people's accounts of, you know, like a journalist, for example, who bought a kit and never had a gun before and how many hours it took them to put together, go on YouTube and see methods for finishing receivers. And I've never done it, so I can't testify how hard that is. But at least some people say it's pretty easy. And there is a long American tradition of sort of gunsmithing. I think people like to associate themselves with that. But as a legal matter, it raises this really hard question of like, well, what is a gun? Like when does it become a firearm? Do you have to wait until the firing pin is in? Like is it when the mechanism is fully? And that in some ways, I think, tracks the question here of like, well, what is a machine gun is exactly the question here. In the constitutional realm, we have a lot of cases about what the Second Amendment refers to as arms. What is an arm? Does an arm cover what are sometimes called gravity knives? Does it cover nunchucks? There was a great Second Amendment case about that that then Judge Sotomayor wrote. Does it cover high-capacity magazines? Like these are all category questions, frankly, just kind of hard to answer. So in some respects, this is a very narrow, lawyerly, technical case about just how to interpret these words, and not about whether bump stocks are a good idea or whether they can be prohibited. It's just whether does this statute actually permit the ATF to regulate them like machine guns.

Host Joel Cohen: That's a big point that was probably, I think, missed in the headlines, which is this isn't to say that Congress couldn't go and ban bump stocks. This particular opinion did not prohibit that. It just said that the original decision on the original executive order, am I right?

Professor Joseph Blocher: Original text of the statute and then the agency regulation based on that statute. But you're exactly right, Joel. I think a lot of people looked at this like it's a big win for gun rights and it is a loss for gun regulation if you like, but it is emphatically not a Second Amendment case. And actually, the majority is very clear about that. This is on Congress. If Congress wants to fix it, they can. Now that may be kind of a hollow hope. It's really hard to imagine, at least in the days, we're only here about a week out from Cargill being decided, you know, Congress has tried and failed to get a new bill going. It seems unlikely to me that that'll happen, but it would, the court here at least says that would not be, we're not deciding whether that would be a Second Amendment problem. To my knowledge, no federal court has yet weighed in on whether bump stocks are covered by the Second Amendment. But if Congress were to pass such a regulation, then we might get a case. And I guess I should also emphasize almost 20 states prohibit bump stocks. So you could have litigation against the state laws even though there's no longer federal regulation and seems unlikely to be federal law.

Host Joel Cohen: Joseph Blocher teaches at Duke Law School and is the co-director of the Duke Center for Firearms Law. Thanks so much for your time today on what I know has been an incredibly busy week, Professor.

Professor Joseph Blocher: Thanks so much for having me, Joel. It's always a pleasure.