The Foreign Intelligence Surveillance Act, which Congress passed in the aftermath of President Richard Nixon's use of the CIA and the FBI to spy on his political opponents, has unleashed demons that now seem beyond the government's control and are more pervasive than anything Nixon could have dreamed of.

This realization came to a boiling point last weekend when President Donald Trump accused former President Barack Obama of monitoring his telephone calls during the 2016 presidential election campaign. Can a U.S. president legally spy on a political opponent or any other person in America without any suspicion, probable cause or warrant from a judge? In a word, yes.

Here is the back story.

The president can order the National Security Agency to spy on anyone at any time for any reason, without a warrant. This is profoundly unconstitutional but absolutely lawful because it is expressly authorized by the FISA statute.