The Foreign Intelligence Surveillance Act (FISA) is a U.S. law enacted in 1978 that regulates the government's ability to conduct surveillance on foreign entities. It allows the government to collect intelligence on foreign powers and agents suspected of espionage or terrorism while providing certain protections for U.S. citizens. FISA established the Foreign Intelligence Surveillance Court (FISC), which reviews and approves surveillance requests. This process aims to balance national security needs with civil liberties, ensuring that any surveillance conducted is lawful and justified under the law.