Less than two weeks after the Supreme Court allowed President Donald Trump to use a controversial 18th century wartime authority to speed deportations, the issue has rocketed back to the justices in a second short-fuse appeal with enormous potential consequences.

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 halted the administration’s ability to use the Alien Enemies Act to swiftly deport migrants to El Salvador who are being detained in portions of Texas, for