The U.S. Department of Justice sued Denver on Tuesday over the city’s longstanding ban on assault weapons and large-capacity magazines, making good on its threat to do so if city officials did not end the ban voluntarily.
City officials responded to the Trump administration’s threat to sue with defiance Monday, vowing to defend the city’s 37-year-old ordinance. The city law prohibits the sale or possession of assault weapons, defined as semiautomatic pistols or centerfire rifles with a fixed or detachable magazine that can carry more than 15 rounds, as well as any semiautomatic shotgun with a folding stock or a magazine capacity of six or more rounds.
The Justice Department lawsuit argues that the city’s ban is unconstitutional and runs afoul of the Second Amendment’s right to bear and keep arms.
“The Constitution is not a suggestion and the Second Amendment is not a second-class right,” Acting Attorney General Todd Blanche said in a news release. “Denver’s ban on commonly owned semi-automatic rifles directly violates the right to bear arms. This Department of Justice will vigorously defend the liberties of law-abiding citizens nationwide.”
The Justice Department filed the lawsuit a day after city officials stood on the steps of the Denver City and County Building and vowed to defend the ban after receiving the demands and threat of a lawsuit last week.
“There are too many Coloradans we’ve had to say goodbye to in too many places because of the impact of assault weapons,” Denver Mayor Mike Johnston said during Monday’s news conference. “…We’ve actually refused to accept the status quo and made significant changes that made the state safer.”
The Justice Department also demanded Colorado officials end the state’s ban on large-capacity magazines or face a lawsuit. No complaint had been filed against the state by mid-afternoon Tuesday.
Dudley Brown, president of Rocky Mountain Gun Owners, welcomed the lawsuit.
“Denver politicians have spent decades pretending the Second Amendment stops at the city limits,” he said in a news release. “Today, the Department of Justice has put them on notice. You do not get to shred the Constitution, criminalize peaceable gun owners and call it public safety. Denver’s gun ban is unconstitutional, immoral and long overdue for the ash heap of history.”
The Second Amendment protects the right of “law-abiding citizens to keep and bear arms in common use for lawful purposes,” the Justice Department complaint reads.
Rocky Mountain Gun Owners sued over Colorado’s large-capacity magazine ban in 2022, but withdrew the case in 2024 after they could not about the “common use” of large-capacity magazines, city attorney Miko Brown wrote in Denver’s on Monday.
The former chief counsel for the Colorado gun rights organization, Barry Arrington, is now the acting chief of the Department of Justice’s Second Amendment Section, according to the complaint, which lists him among several attorneys on the case.
