President Trump says he’s using the 227-year-old law to crack down on Venezuela’s Tren de Aragua gang. The move is already facing a legal challenge. Here’s a look at key questions and answers about the Alien Enemies Act.

President Trump has invoked the 18th-century Alien Enemies Act to allow the federal government to detain or deport people from countries deemed foreign adversaries, including targeting cartels as foreign terrorist organizations.