The Foreign Intelligence Surveillance Act of 1978 (FISA) regulates, among other things, the government’s acquisition of electronic surveillance within the United States for foreignintelligence purposes. FISA allows a federal officer to seek an order from a judge at a specially designated court “approving electronic surveillance of a foreign power or an agent of a foreign power for the purpose of obtaining foreign intelligence information.” As long as the requisite foreign nexus can be shown, FISA warrants are preferable to their possible substitutes because they are easier to obtain and allow for more secretive and penetrating investigations. Consistent with FISA’s foreign focus, the government may use the statute to investigate members of international terrorist groups within the United States. However, the activities of purely domestic terrorist groups do not fall under FISA and must therefore be investigated using standard criminalinvestigative tools. Often, terrorists will easily be identified as international; members of designated “foreign terrorist organizations” operating within the United States are clearly international terrorists. But the proliferation of modern communication technologies has caused increasing slippage between the definitions of domestic and international terrorism. For example, many homegrown terrorists are inspired by international groups to commit attacks in the United States. In many cases, the government seems to classify these actors as international terrorists based on Internet activity that ranges from viewing and posting jihadist YouTube videos to planning attacks with suspected foreign terrorists in chat rooms, thus using FISA’s formidable investigatory weapons against them. The government is aided in this task by FISA’s definition of international terrorism, which has an extremely vague and potentially loose internationality requirement. An expansive interpretation of this requirement could be used to subject what might properly be considered domestic terrorist groups to FISA surveillance. One should be concerned about both the existence and the effects of an expansive interpretation of FISA’s internationality requirement. Not only would subjecting domestic terrorist groups to FISA surveillance violate FISA itself, but such an application might also be unreasonable under the Fourth Amendment. Moreover, the FISA application and surveillance process is very secretive, lacks a true adversarial process, and is devoid of meaningful oversight. This setting offers an ideal environment for the government to push statutory and constitutional boundaries. Indeed, recent revelations from Edward Snowden offer confirmation that the government is more likely to cross constitutional lines in the name of national security when these institutional factors are present.