Washington, D.C., officials are taking the Trump administration to court over what they call an unlawful federal seizure of the city’s police force, a move that’s now escalated into a showdown over immigration enforcement and the city’s limited right to self-government.

Washington, D.C., sued the Trump administration Friday, alleging the president overstepped his authority in a takeover of the Metropolitan Police Department—legal action that comes a day after the Trump administration attempted to effectively replace D.C.’s police commissioner with a federal official.