This chapter explores shifting patterns of intelligence surveillance in the United States. The Fourth Amendment protects Americans from unreasonable search and seizure without a warrant, but foreign spying is subject to few constraints. During the Cold War, surveillance power was abused for political purposes. Operating in a culture of secrecy, American intelligence agencies engaged in extensive illegal domestic spying. The intelligence scandals of the 1970s revealed these abuses, prompting new laws, notably the Foreign Intelligence Surveillance Act. Fearing further recrimination, the national security establishment increasingly demanded legal cover. After 9/11, Congress expanded lawful surveillance powers with the PATRIOT Act. Meanwhile, the Bush administration directed the National Security Agency to conduct warrantless domestic wiretapping. To justify this program, officials sought to redefine unconstrained foreign surveillance to subsume previously protected communications. The Obama administration continued to authorize mass surveillance and data mining programs and legally rationalize bulk collection of Americans’ data.
