The Foreign Intelligence Surveillance Act (FISA) was first enacted in 1978 (Public Law 95-511) and later amended, including in 1994, by the Patriot Act, and by the 2008 FISA Amendments Act. It was at the center of the controversy concerning domestic spying by the National Security Agency. It was passed after revelations of massive domestic spying abuses by the FBI, CIA and NSA were documented in reports issued by the Church Committee in the 1970s. In 1972, the United States Supreme Court reviewed some of those abuses and declared that warrantless wiretaps of domestic groups for national security reasons violated the Fourth Amendment. United States v. United States District Court (Keith), 407 U.S. 297 (1972).
The FISA provided special procedures for conducting electronic surveillance of telephones, etc. for foreign intelligence purposes including setting up a Foreign Intelligence Surveillance Court to authorize such surveillance. 50 U.S.C. 1801 et seq. The Act provides for surveillance of American citizens and others for whom the court determines that there is probable cause that they are "agents of a foreign power" as defined in the statute.
Warrantless Wiretapping and Electronic Surveillance, J. Hearings Before the Subcomm. on Administrative Practice and Procedure and the Subcomm. on Constitutional Rights of the Senate Comm. on the Judiciary and the Subcomm. on Surveillance of the Senate Committee on Foreign Relations, 93rd Cong. part I(a), part I(b) & part II(a), part II(b), part II(c). (April 3, 8, 1974 & May 8, 9, 10, and 23, 1974).
Electronic Surveillance for National Security Purposes, Hearings Before the Subcomm. on Criminal Laws and Procedures and Constitutional Rights of the Committee on the Judiciary of the United States Senate, part I(a), part I(b), part I(c) and part II(a), part II(b), part II(c), 93rd Cong. (October 1, 2 and 3, 1974).
Foreign Intelligence Surveillance Act of 1976, Hearings on S. 743, S. 1888 and S. 3197 Before the Subcomm. on Criminal Laws and Procedures of the Senate Comm. on the Judiciary, 94th Cong. (March 29 & 30, 1976).
Foreign Intelligence Surveillance Act, Hearings before the Subcomm. on Courts, Civil Liberties, and the Administration of Justice of the House Comm. on the Judiciary, part I(a), part I(b), 94th Cong. (April 12, May 5, and June 2, 1976).
Electronic Surveillance Within the United States for Foreign Intelligence Purposes, Hearings on S. 3197 Before the Subcomm. on Intelligence and the Rights of Americans of the Senate Select Comm. on Intelligence, part I(a), part I(b), part I(c), 94th Cong. (June 29, July 1, August 6, 10, & 24, 1976).
Foreign Intelligence Surveillance Act of 1977, Hearings on S. 1566 Before the Subcomm. on Criminal Laws and Procedures of the Senate Comm. on the Judiciary, part I(a), part I(b), 95th Cong. (June 13 and 14, 1977).
Foreign Intelligence Surveillance Act, Hearings on H.R. 5794, H.R. 9745, H.R. 7308 and H.R. 5632 Before the Subcomm. on Legislation of the House Permanent Select Comm. on Intelligence, part I(a), part I(b), part I(c), 95th Cong. (January 10, 11, 17 and February 8, 1978).
Foreign Intelligence Surveillance Act, before the Subcomm. on Courts, Civil Liberties and the Administration of Justice of the House Comm. on the Judiciary House of Representatives, part I(a), part I(b), 95th Cong. (June 22, 28, and 29, 1978).
Foreign Intelligence Surveillance Act of 1978, before the Subcomm. on Intelligence and the Rights of Americans of the Senate Select Comm. on Intelligence, part I(a), part I(b), part I(c), 95th Cong. (July 19, 21, 1977 & February 8, 24, 27, 1978).
In 1978, the Congress had refused to authorize secret warrantless searches of homes and offices. After Attorney General Reno authorized a secret search of CIA spy Aldrich Ames' home and his attorney challenged it, the Clinton administration asked Congress to extend FISA to authorize secret physical searches of Americans' homes and offices. The civil liberties community objected that such secret searches are unconstitutional, but the Justice Department argued that it was better to have such searches authorized by the FISA Court than carried out solely on the signature of the Attorney General as had occurred in the investigation of Aldrich Ames.
In the summer of 1994 the House Intelligence Committee held a hearing to consider the Administration's proposal to extend the FISA to include physical searches:
During late summer 1994, Congressman Don Edwards opposed extending the FISA to authorize secret searches and Attorney General Janet Reno responded.
Congress amended the FISA to authorize secret physical searches with the Counterintelligence and Security Enhancements Act of 1994, Public Law 103-359, Sec. 9. Afterwards, the Supreme Court ruled in a different context that the Constitution requires the government to give individuals "knock and notice" when searching their homes, as the civil liberties community had argued that it did. Wilson v. United States, 514 U.S. 927 (1995).
The Supreme Court has not yet ruled whether this notice requirement means that secret searches under the FISA are unconstitutional. See Center for National Security Studies amicus brief in U.S. v. Squillacote, March 20, 1998.
In 1999, the FISA was again amended to provide for FISA court orders for pen registers, trap and trace devices, and certain business records of suspected agents of a foreign power. Intelligence Authorization Act for Fiscal Year 1999, Sections 601 and 602, Public Law 105-272.
In 2000, Congress expanded the definition of "agent of a foreign power" to include people working for a foreign government who intentionally enter the United States with a fake ID or who obtain a fake ID while inside the U.S. Intelligence Authorization Act for Fiscal Year 2000, Section 601, Public Law 106-120.
In 2001, the FISA was amended to clarify which federal officials could authorize applications to the FISC for electronic surveillance and physical searches. Intelligence Authorization for Fiscal Year 2001, Sections 602 and 603, Public Law 106-567.
In 2001, the Patriot Act made extensive changes to the FISA, broadening the circumstances when the secret FISA authorities could be used and eliminating some of the safeguards against abuse.
In 2002, the FISA was amended to permit the Attorney General to wait 72 hours - rather than 24 hours - before seeking a court order after authorizing electronic surveillance in emergency situations. Intelligence Authorization Act for Fiscal Year 2002, Section 314, Public Law 107-108.
In 2004, Congress added the "lone wolf" provision. It amended the definition of who could be targeted under FISA to eliminate the requirement that non-U.S. persons be acting on behalf of a foreign power in order to be targeted. Intelligence Reform and Terrorism Prevention Act of 2004, Section 6001, Public Law 108-458.
After the December 2005 revelations, that the NSA had engaged in warrantless wiretapping in violation of the FISA, Congress penned the Protect America Act in 2007. It replaced that law with the FISA Amendments Act in 2008, which was then renewed in 2012.
The USA Freedom Act was signed into law on June 2, 2015. The Act makes clear that Congress does not authorize the mass collection by the NSA of the metadata of all communications by Americans – whether by telephone or internet – while preserving the government’s capability to retrieve the metadata of communications by suspected terrorists. The Act does so by amending not only the business records provision of the PATRIOT Act, section 215, but also by amending the pen register/trap and trace provisions of the FISA that were used by the NSA for bulk collection of Americans’ internet metadata, and by amending national security letter authorities so that they may not be used for such bulk collection. The Act requires greater transparency about the operations of the Foreign Intelligence Surveillance Court, by mandating disclosure concerning rulings by the Court, a necessary step to prevent the use of secret law for the secret surveillance of Americans. It also requires additional public reporting concerning the use of these surveillance authorities and requires internal reviews by agency Inspectors General.