The Supreme Court today struck down a ban on bump stocks, which enable semiautomatic rifles to fire rapidly like machine guns. The ban was enacted by the Trump administration after a deadly mass shooting in Las Vegas in 2017.

The decision, by a vote of 6 to 3, split along ideological lines. Justice Clarence Thomas, writing for the majority, found that the Bureau of Alcohol, Tobacco, Firearms and Explosives had exceeded its authority when it banned the sale and possession of the device.

Justice Sonia Sotomayor filed a dissent along with two other judges, saying the decision “puts machine guns back in civilian hands.” President Biden urged Congress to act to ban the device.

The man who challenged the bump stock ban, a gun shop owner in Texas, said that the ruling was a broader victory for gun rights and that it would make it easier to challenge future attempts by the A.T.F. to regulate firearms.

During the shooting in Las Vegas, Stephen Paddock fired on a music festival from the 32nd floor of a hotel, killing 60 people and injuring hundreds. In his arsenal were a dozen AR-15-style rifles outfitted with bump stocks. In about 11 minutes, he fired more than 1,000 rounds of ammunition.

The ban was a rarity in an era of deep division over gun violence: a restriction that won support from Democrats, Republicans and even the National Rifle Association.