The Supreme Court on Friday struck down a ban on bump stocks, which enable semiautomatic rifles to fire at speeds rivaling those of machine guns, erasing one of the government’s rare firearm regulations to result from a mass shooting.
The decision, by a vote of 6 to 3, split along ideological lines. Justice Clarence Thomas, writing for the majority, said that the Bureau of Alcohol, Tobacco, Firearms and Explosives had exceeded its power when it prohibited the device by issuing a rule that classified bump stocks as machine guns.
“We hold that a semiautomatic rifle equipped with a bump stock is not a ‘machine gun’ because it cannot fire more than one shot ‘by a single function of the trigger,’” Justice Thomas wrote. His opinion included several diagrams of the firing mechanism, and he described in technical detail the internal workings of a firearm to show how a bump stock works.
The Trump administration enacted the ban after a gunman opened fire at a Las Vegas concert in 2017, one of the deadliest massacres in modern American history.
The decision was a forceful rejection of one of the government’s few steps to address gun violence, particularly as legislative efforts have stalled in Congress. It also highlighted the deep divisions on the court as the country continues to grapple with mass shootings.