Section 740 of the Home Rule Act allows for the president to take over Washington’s Metropolitan Police Department for 48 hours, with possible extensions to 30 days, during times of emergencies. No president has done so before, said Monica Hopkins, executive director of the ACLU of Washington.

President Trump said yesterday that he was temporarily taking control of the police force in Washington and deploying 800 National Guard troops to fight crime in the U.S. capital.