The U.S. Department of Justice has hauled the City and County of Denver and the Denver Police Department into federal court, filing suit on Tuesday, May 5, and asking a judge to halt enforcement of the city’s 37-year-old ordinance that bans so-called “assault weapons.” The complaint argues the law criminalizes possession of commonly owned semiautomatic rifles and standard-capacity magazines and seeks both declaratory and injunctive relief.
DOJ files suit in federal court
According to the U.S. Department of Justice, the agency filed a 12-page complaint in the U.S. District Court for the District of Colorado naming the City and the Denver Police Department as defendants. Acting Attorney General Todd Blanche called the ordinance unconstitutional, and Assistant Attorney General Harmeet K. Dhillon said the Civil Rights Division’s new Second Amendment Section will press the case. The DOJ asked the court for a permanent injunction barring enforcement of the ordinance while the litigation proceeds.
What the complaint alleges
The complaint (Case No. 1:26-cv-01929), filed May 5, 2026, says Denver Revised Municipal Code ch. 38, art. IV, § 38-121(c) makes it, in the filing's words, “It shall be unlawful to carry, store, keep, manufacture, sell, or otherwise possess assault weapons” within the city, and it defines the term to include semiautomatic rifles or pistols with magazines that hold more than 15 rounds. As filed, the government asks the court to use the Civil Rights Division's authority and to enjoin enforcement of the ordinance; the full text of the complaint is available in the U.S. Department of Justice.
City Hall pushes back
Mayor Mike Johnston, joined by public-safety leaders, rejected the DOJ demand and vowed the city will defend the law, saying the ordinance “works, it saves lives, and it reflects the values of our community,” as reported by the Denver Gazette. Denver City Attorney Miko Brown called the DOJ request “baseless, irresponsible, and a clear overreach of the federal government's power” and said the city “will vigorously defend its ordinance if challenged.” Local reporting notes the filing followed an April pre-suit letter from the DOJ that asked Denver to immediately cease enforcement and enter negotiations instead; Denver refused that demand.
Why Bruen matters
The complaint explicitly invokes the Supreme Court’s 2022 decision in New York State Rifle & Pistol Ass'n v. Bruen, arguing that modern firearms regulations must be judged against the Nation’s historical tradition of firearm regulation rather than by interest-balancing. The filing also points to data showing millions of AR-style rifles in circulation to support the claim that those arms are “in common use,” a threshold the DOJ says shields them under Heller and Bruen; see Oyez for the decision’s framework.
What happens next
The DOJ is asking the court to bar Denver police from making arrests or seizing property based on possession of the covered rifles and magazines while the litigation proceeds, a remedy described in the department's press release. Denver officials say they will answer the complaint and defend the ordinance in court. If the case advances, it could produce rapid rounds of motions and appeals and become a significant test of how Bruen applies to weapon-specific municipal bans.
Legal implications
The government brought the suit under the pattern-or-practice authority created by the Violent Crime Control and Law Enforcement Act of 1994, which allows the Attorney General to seek injunctive relief against local practices the department says deprive people of constitutional rights, as reflected in the law's text on Congress.gov. How the court applies Bruen's history-and-tradition test to Denver's decades-old, weapon-specific ban will help determine whether similar local restrictions across the country can survive post-Bruen review.
