Three of the four acts expired shortly after they were signed into law in the late 1700s. One remains active-and it's been at the center of constitutional debates ever since.

What is the Alien Enemies Act? It's an 18th-century law that allows the president to detain or deport immigrants from countries the U.S. is at war with. In more than 225 years, the law had been ...

Donald Trump is expected to invoke a rarely-used Alien Enemies Act of 1798 in an effort to ramp up deportations.