Lummis Leads Supreme Court Brief Defending Wyoming Gun Owners from ATF Effort to Outlaw Bump Stocks

January 26, 2024

WASHINGTON, D.C. – Today, U.S. Senator Cynthia Lummis (R-WY) alongside 8 other U.S. Senators and multiple legal experts filed an amici curiae brief in the U.S. Supreme Court case Garland v. Cargill. The brief asserts the Bureau of Alcohol Tobacco and Firearms (ATF) ban on bump stocks under the National Firearms Act is not only an egregious violation of the people of Wyoming’s right to bear arms but also represents a dangerous new frontier of federal bureaucrats interpreting federal law in expansive new ways Congress clearly did not intend, including by weaponizing the Chevron doctrine to create new federal crimes out of thin air.

“The ATF’s job is to interpret existing laws passed by Congress, not grant itself sweeping authority to confiscate firearms from law-abiding Wyoming gun-owners as is the case with the bump stock ban,” said Lummis. “Garland v. Cargill represents a true fork-in-the-road moment for gun rights in America. The people of Wyoming have a long history of responsible gun ownership to protect their family and property, and I will not allow gun grabbers in Washington to change that.” 

“We cannot allow unelected bureaucrats at the ATF to abuse their authority and interpret laws in a way Congress clearly never intended. This case is critical to preserving our Second Amendment rights and preventing the kind of gun-grabbing overreach far-left activists are desperate to see,” said Ricketts.

“Biden’s Justice Department and ATF have demonstrated again and again that the law, congressional intent, and the Constitution don’t matter when it comes to their goal to infringe on the Second Amendment rights of law-abiding gun owners.  In this brief we make the case that these actions are clearly unconstitutional and that the anti-gun administrative state needs to have its wings clipped,” Hyde-Smith said.

“The ATF’s bump stock ban is yet another example of bureaucrats abusing their authority to infringe on the Second Amendment rights of the American people,” said Rounds. “There are many examples of regulatory overreach by the ATF throughout its history, with policy changes based on deliberate misinterpretations of text and intent of legislation passed by Congress. I’m pleased to join this effort to hold regulators accountable and defend the rights of law-abiding gun owners.”  

“Biden has weaponized the ATF to come after law abiding Montana gun owners and it must be stopped. The Second Amendment is clear—the right to keep and bear arms shall not be infringed, and a ban on bump stocks would threaten Montanans’ constitutional right to defend themselves and their families,” said Daines.

“Joe Biden will stop at nothing to undermine the fundamental constitutional rights of law-abidingAmericans,” said Mullin. “Making up new felonies through the rulemaking process and outlawing attachments like pistol braces and bump stocks, is simply a means to an end: taking away your guns. I am proud to join my Senate colleagues on this amicus brief, and I look forward to winning this fight to protect the Second Amendment in court.”

Senators John Barrasso (R-WY), Mike Lee (R-UT), Kevin Cramer (R-ND), Pete Ricketts (R-NE), Steve Daines (R-MT), Cindy Hyde-Smith (R-MS), Mike Rounds (R-SD) and Markwayne Mullin (R-OK) joined Lummis in filing the brief. The senators were also joined by University of Wyoming Law Professor George A. Mocsary, Independence Institute Counsel David B. Kopel, and the leading professors of Second Amendment and firearms law in the United States.


  • Michael Cargill, the plaintiff, bought two bump stocks in April 2018, before the ATF issued its final rule outlawing them, but turned in the devices in March 2019 after the ban went into effect. 
  • That same day, he filed a lawsuit in federal district court in Texas challenging the ban on numerous grounds.
  • The district court sided with the federal government and upheld the ban.
  • A three-judge appeals court panel of the Fifth Circuit agreed with the district court’s conclusion that bump stocks qualify as machineguns under federal law, and were subject to a 1986 ban under the National Firearms Act.
  • However, the full U.S. Court of Appeals for the Fifth Circuit reversed the lower court’s decision.
  • Following the ruling by the Fifth Circuit, the Biden administration asked the U.S. Supreme Court to weigh in.  

Click here to read the brief.