In addition to protecting government buildings and personnel, the Pentagon has said the troops will safeguard Immigration and Customs Enforcement officers during raids.
ICE posted photos online on Tuesday of National Guard troops standing guard with weapons in hand as ICE officers handcuffed apparent migrants against the side of a car in Los Angeles.
An 1878 law, the Posse Comitatus Act, generally forbids the U.S. military, including the National Guard, from taking part in civilian law enforcement.