The Foreign Intelligence Surveillance Act (FISA) was enacted in 1978 in response to revelations of widespread privacy violations by the federal government under President Nixon. It established procedures for requesting judicial authorization for electronic surveillance and physical search of persons engaged in espionage or international terrorism against the United States on behalf of a foreign power1 The original purpose of FISA was to further define a framework for authorizing wiretaps by the executive branch for national security purposes under Article II of the Constitution, which grants the president the power to conduct foreign affairs and defend the nation23 FISA was intended to balance the need for collecting foreign intelligence information with the protection of privacy and civil liberties of
U.S. persons4 References: https://www.intelligence.gov/foreign-intelligence-surveillance-act
https://www.intelligence.gov/foreign-intelligence-surveillance-act/1234-categories-of-fisa