Nunes memo centers on a 40-year-old law written to prevent surveillance abuses

At the center of the firestorm over a congressional memo that President Trump and his allies say reveals federal authorities’ missteps is a 40-year-old law passed in the wake of explosive domestic spying scandals. The Foreign Intelligence Surveillance Act (FISA) grew from congressional investigations into spy agencies’ eavesdropping on Americans, including civil rights activists and protesters against the Vietnam War, without warrants. The law created a warrant requirement for federal authorities to intercept the communications of anyone in the United States, including foreigners. It says the Justice Department must prove to a federal judge that there is probable cause to believe any American target is an agent of a foreign power and engaged in acts such as spying on behalf of a foreign government. Now, the House Intelligence Committee’s Republican leadership, which plans to release the memo, suggests a politicized FBI and Justice Department abused the law to put surveillance on a former Trump campaign aide to advance an investigation into Russian meddling in the 2016 election. Lost in the noise are some of the fundamentals about the surveillance law. FISA has several parts, but the one at issue now is the least controversial. Title I of FISA governs intercepts of phone calls and emails, and it requires a detailed paper trail, with evidence presented to a federal judge that is first reviewed at several levels of the Justice Department.