Trump administration sues Denver over ICE mask ban

Driving the news: The U.S. Department of Justice filed the lawsuit against Denver, Mayor Mike Johnston, City Attorney Miko Brown and police chief Ron Thomas.

• The DOJ argues the city ordinance violates the Constitution's Supremacy Clause, which limits local authority over federal operations.

• It wants a judge to permanently block Denver from enforcing the ban against federal officers.

Catch up quick: Denver City Council unanimously approved the ordinance in March. It bans law enforcement officers from concealing their faces during arrests and detentions.

• It also requires officers to display ID, with exceptions for undercover work and certain safety situations.
• Violators could face up to 300 days in jail and a $999 fine, according to the complaint.

Zoom in: Federal attorneys argue the restrictions expose officers to harassment and retaliation.

• The lawsuit cites recent court rulings blocking similar restrictions in California, New York, Virginia and Philadelphia.

The other side: The city is standing by the ordinance as a transparency and accountability measure.

• "Denverites deserve to know who is arresting them and what they're being arrested for," Johnston spokesperson Jon Ewing told Axios in a statement.

The big picture: Denver and the Trump administration have repeatedly clashed over immigration enforcement.

• The DOJ sued Denver and Colorado last year over policies limiting cooperation with ICE.
• In February, Johnston largely barred ICE agents from city property.
• Last month, Denver filed a lawsuit to block ICE from polling places.

What's next: A federal judge will decide whether Denver can regulate how federal officers identify themselves and what they wear.