The Biden administration has asked the U.S. Supreme Court to hear its appeal of a lower court ruling against a federal ban on “bump stock” devices, which enable semiautomatic weapons to fire like Machine Guns. The administration is defending the ban, imposed under former President Donald Trump, against a challenge by Michael Cargill, a gun shop owner and gun rights advocate from Austin, Texas. The ban was a rare firearms control measure in the United States prompted by a 2017 mass shooting in Las Vegas.

In January, the New Orleans-based 5th U.S. Circuit Court of Appeals sided with Cargill, concluding that the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), a U.S. Justice Department agency, impermissibly reclassified Bump Stocks as machine guns, which are forbidden under U.S. law. That decision “threatens significant harm to public safety,” the Justice Department said in its appeal on Friday. “Bump stocks allow a shooter to fire hundreds of bullets a minute by a single pull of the trigger. Like other machine guns, rifles modified with bump stocks are exceedingly dangerous.”

Three other federal appeals courts previously upheld the bump stock ban. The Supreme Court, which expanded gun rights in a significant decision last year, declined to review those cases.

Bump stocks use a semiautomatic recoil to allow it to slide back and forth while “bumping” the shooter’s trigger finger, resulting in rapid fire. After a gunman used weapons outfitted with bump stocks in a 2017 shooting spree at a country music festival in Las Vegas, killing 58 people and wounding hundreds more, Trump’s administration moved to review their legality.

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In its 2019 rule, ATF reversed a previous conclusion and classified bump stocks as machine guns, defined under a 1934 law called the National Firearms Act as weapons that can “automatically” fire more than one shot “by a single function of the trigger.” Federal law prohibits the sale or possession of machine guns, punishable by up to 10 years in prison.

Cargill sued, challenging the ATF’s rule in 2019, which required him to surrender his two bump stocks. The New Civil Liberties Alliance, a conservative legal group, represents him.

In January, a full slate of 5th Circuit judges ruled 13-3 in Cargill’s favor but left it for a trial judge to determine whether to throw out the ATF rule.

The Supreme Court, in a 6-3 ruling powered by its conservative justices in June 2022, declared for the first time that the U.S. Constitution protects the right to carry a handgun in public for self-defense.

Two days after that ruling, Biden so law the first major federal gun law reform in three decades. The legislation followed mass shootings in Uvalde, Texas, and Buffalo, New York that killed over 30 people, including 19 children at an elementary school.

It remains to be seen whether the Supreme Court will hear the Biden administration’s appeal and decide on the bump stock ban. However, with the recent expansion of gun rights in the Supreme Court’s major decision last year, and the passage of the first major federal gun reform in three decades, firearms control will likely remain a contentious and highly debated topic in the United States.