Elected last year on a promise to crack down on migrants, Trump invoked the 1798 Alien Enemies Act in an attempt to swiftly deport accused members of Tren de Aragua, a criminal gang originating from Venezuelan prisons that his administration labels a terrorist group.

The U.S. Supreme Court temporarily blocked the removal of Venezuelan detainees accused under a wartime law of being foreign gang members early Saturday morning, after the ACLU argued the men were at risk of imminent removal to an El Salvadoran prison.