The Alien Enemies Act, an 18th century law, gives the president sweeping authority during a time of war to deport people from an enemy nation. It was used to legitimize Japanese internment during World War II. Trump has invoked the law claiming that Venezuelan gangs have invaded the United States.

The Supreme Court early Saturday morning paused the deportation of immigrants potentially subject to the Alien Enemies Act, freezing action in a fast-developing case involving a group of immigrants in Texas who say the Trump administration was working to remove them.