DOJ Sues Denver Over ICE Mask Ban: What the Ordinance Says and What's Next

DENVER — The Justice Department has sued Denver over a city law that bars federal immigration agents and other officers from covering their faces while they work in the city, setting up a test of how far a local government can go in policing federal agents.

The lawsuit, filed Oct. 8 in U.S. District Court in Colorado, names the city, Mayor Mike Johnston, City Attorney Miko Brown and Police Chief Ron Thomas. It asks a judge to declare the ordinance invalid as applied to federal law enforcement and to permanently block Denver from enforcing it.

Johnston said on Instagram that the city would “fight to the very end on this battle.” Officers, he said, “should have a badge, they should have a name, they should have a badge number that you can track.”

The City Council passed the ordinance unanimously in February. It applies to every law enforcement officer working in Denver, local, state or federal. Officers may not cover their faces while detaining or arresting someone, and they must display visible identification. Denver police can cite violators, and the penalty can reach a $999 fine and up to 300 days in jail, Denver7 reported.

The Justice Department’s main argument is the Supremacy Clause of the U.S. Constitution, which makes federal law override conflicting state and local laws. Threatening officers with prosecution for protecting their identities “chills the enforcement of federal law,” the department said in announcing the suit.

The complaint also argues that complying “would endanger officers and reduce operational effectiveness.” It says the families of two federal agents, one in the Denver area and one in Durango, were doxxed and harassed after the agents’ images were posted online. Filming officers in public is protected by the First Amendment, the government acknowledged, but it said posting their identities online can help criminal organizations target them.

“Denverites deserve to know who is arresting them and what they’re being arrested for,” said Jon Ewing, a spokesman for the mayor, in a statement to The Denver Post.

Denver is not the first to try this, and the record so far favors the federal government. Los Angeles, New York, Seattle, Chicago, Milwaukee and Philadelphia all adopted similar mask bans this year, and most have been blocked by federal judges or are tied up in federal court, Denver7 reported. Earlier this year a California judge struck down a state anti-masking law because it exempted state officers while applying to federal ones. Denver’s council wrote its ordinance to cover every level of law enforcement, including its own police, in the hope of avoiding the same problem.

The fight is part of a wider standoff between Denver and the Trump administration. Days after signing the mask ordinance, Johnston signed an executive order barring Immigration and Customs Enforcement from city-owned or city-controlled property, and the city has sued to keep armed federal immigration agents away from polling places during the midterm elections.

Local officers would be the ones writing any citations, and their union has questions. Brian Pacelko, president of the Denver Police Protection Association, has asked what would happen if a federal agent tried to charge a Denver officer for enforcing the law. The Denver Police Department said discretion and de-escalation are its priorities.

Frequently asked questions

What does Denver’s mask ban require?

Law enforcement officers working in Denver, including federal immigration agents, may not cover their faces while detaining or arresting people and must display visible identification. Violations can bring a citation with a fine of up to $999 and up to 300 days in jail.

Why is the Justice Department suing?

The department argues the ordinance violates the Supremacy Clause because a city cannot regulate how federal officers carry out federal law, and says the rule would expose agents to doxxing and threats.

Have other cities passed similar laws?

Yes. Los Angeles, New York, Seattle, Chicago, Milwaukee and Philadelphia adopted similar bans in 2026. Most have been blocked by federal judges or are being challenged in federal court.