The Department of Justice (DOJ) on Tuesday announced it is filing a lawsuit against Denver, Colorado, over the city’s ban on AR-15-style rifles with standard-capacity magazines, after the city’s mayor refused to repeal the ban a day prior.
In a lawsuit filed in the U.S. District Court for the District of Colorado, the DOJ said the city’s ban on AR-15-style firearms and other firearms, which local officials term “assault weapons,” goes against the Constitution’s Second Amendment and fails to adhere to a landmark Supreme Court ruling in 2022 that bolstered the right for Americans to carry and obtain guns.
The firearms prohibited in the city’s ban “include ordinary semiautomatic rifles possessed by millions of law-abiding Americans,” said the DOJ in a 12-page complaint, noting that Americans “own literally tens of millions of AR-15 style rifles” and cited another Supreme Court ruling that said in 2025 that AR-15s are the most common type of rifle in the United States.
“When the City banned AR-15 style rifles with standard capacity magazines, it banned an arm in common use for lawful purposes by law-abiding citizens,” said the Justice Department. “Therefore, the Ordinance violates the Second Amendment, and the United States brings this action to vindicate the rights of Denver citizens whose rights have been—and are continuing to be—violated by Defendants.”
The lawsuit was filed after Denver Mayor Mike Johnston said Monday at a press conference at Denver’s City and County Building that his city won’t repeal the city’s decades-long ban on the weapons.
The Democratic mayor said that the city “will not roll back a common-sense policy” that has remained intact for 37 years and has kept what he called “weapons of war” from being carried on Denver’s streets.
Colorado Attorney General Phil Weiser said Monday that he would work to defend the state’s ban on the weapon, and said that the Colorado Supreme Court upheld the ban in a ruling issued in 2020.
“I believe the law has reasonable limitations that satisfy Second Amendment protections,” Weiser said in a statement to multiple local media outlets. “Large-capacity magazine laws are responsible policies that decrease the deadly impacts of mass shootings and save lives,” he also said, using a term that generally refers to gun magazines that have a capacity of holding more than 10 rounds.
But the DOJ said that the city ordinance banning semi-automatic rifles fails to adhere to the Supreme Court’s 2022 New York State Rifle & Pistol Association, Inc. v. Bruen ruling in which the majority found that the Second Amendment protects an individual’s right to carry a handgun for self defense while also establishing a legal framework that requires gun regulations to align with the United States’ historical tradition on regulating firearms.
“The Ordinance makes it a crime to keep and bear AR-15 style rifles with standard capacity magazines,” the DOJ wrote Tuesday. “AR-15 rifles are bearable arms. Therefore, the Ordinance implicates the plain text of the Second Amendment. Under Bruen step one, the Ordinance is presumptively unconstitutional. As set forth below, Defendants will not be able to rebut this presumption.”
