Tren de Aragua, a gang born out of a Venezuelan prison, is a loose network that doesn’t operate like groups typically considered terrorist organizations.

President Donald J. Trump has unleashed a sweeping offensive against the Tren de Aragua (TdA) gang, signing a proclamation Saturday invoking the Alien Enemies Act to tackle what the White House calls an “invasion” by the Venezuela-born terrorist group.

Administration officials said they expect the fight over using the wartime act to ultimately head to the Supreme Court.