Supreme Court Appears Split Over Ban on Bump Stocks Enacted Under Trump

The Supreme Court wrestled on Wednesday over whether the Trump administration acted lawfully in enacting a ban on bump stocks after one of the deadliest mass shootings in U.S. history.

The justices appeared split largely along ideological lines over the ban, which prohibits the sale and possession of bump stocks, attachments that enable semiautomatic rifles to fire at speeds rivaling machine guns. Some raised concerns about the broader implications of a reversal.

The case does not turn on the Second Amendment right to keep and bear arms. Instead it is one of a number of challenges aimed at curtailing the power of administrative agencies — in this instance, the Bureau of Alcohol, Tobacco, Firearms and Explosives. A decision is expected by late June.

After a gunman stationed on the 32nd floor of a hotel suite opened fire at a country music festival in Las Vegas in 2017, a ban on bump stocks gained political traction, one of the few pieces of gun control legislation to generate significant discussion. Officials at the Justice Department initially said the executive branch could not prohibit the accessory without action by Congress. But it ultimately reversed course and enacted a ban on its own.

At issue is whether a bump stock falls within the legal definition of a machine gun. If the court deems a bump stock can be used to make a gun into a “machine gun,” then it can be prohibited as part of a category heavily regulated by the A.T.F.

During less than two hours of arguments, the justices appeared to struggle to make sense of the mechanics of gun triggers and the value of a ban for gun owners and the wider public.