The Washington, D.C., attorney general sued the Trump administration Friday, alleging the president has 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.

The showdown in Washington is the latest attempt by Trump to test the boundaries of his legal authority to carry out his tough-on-crime agenda, relying on obscure statutes and a supposed state of emergency to speed up the mass deportation of people in the United States illegally.