An appeals court heard arguments Monday over whether the Trump administration can invoke the Alien Enemies Act to deport migrants it says are Tren de Aragua members.

The case is likely to be the first to reach the Supreme Court on the substantive issue of the president’s invocation of a rarely used wartime law.

A federal appeals court heard oral arguments on Monday in what is likely to be a decisive lawsuit over whether President Donald Trump's administration can use an 18th-century law to speed up deportations.