Donald Trump is vowing to invoke a 226-year-old law to justify mass detainments and deportations in the United States, saying that Election Day will be known as “Liberation Day” if he is handed the keys to the White House.

The Alien Enemies Act of 1798 is a widely condemned immigration law that gives the president sweeping powers to bypass equal protection and due process while targeting foreign citizens. When it has been invoked, it has led to human rights crises that history looks down upon — but the law has not formally been repealed by Congress.