This legislation, titled the "Protect Liberty and End Warrantless Surveillance Act of 2026" and the "Fourth Amendment Is Not For Sale Act," aims to significantly reform the Foreign Intelligence Surveillance Act (FISA) and restrict government agencies' ability to acquire sensitive data without judicial oversight. While extending the authority under FISA Title VII (Section 702) until April 20, 2028, the bill introduces substantial new limitations and oversight mechanisms to protect the privacy and civil liberties of United States persons. A central provision prohibits warrantless queries of communications and other information pertaining to United States persons that are collected under Section 702 of FISA. Exceptions to this prohibition are narrowly defined, including situations with concurrent court authorization, genuine emergencies involving imminent threats of harm, explicit consent, or specific defensive cybersecurity queries. The bill also restricts the use of metadata queries as a basis for accessing communications and ensures these prohibitions apply to federated and mixed datasets containing FISA-acquired information. The bill further limits the issuance of FISA directives to certain electronic communication service providers, requiring a declassification review of relevant FISA Court opinions and increased transparency for Congress. It significantly expands the role of amici curiae (friends of the court) in FISA Court proceedings, mandating their appointment in cases presenting novel legal interpretations, significant civil liberties concerns, sensitive investigative matters (such as those involving public officials or the news media), or new surveillance programs. These amici are granted enhanced access to information and the authority to seek review of FISA Court decisions. Under Title II, the legislation prohibits law enforcement and intelligence agencies from purchasing "covered customer or subscriber records" or "illegitimately obtained information" from third-party data brokers. This includes sensitive data like location information, communications content, and online account data pertaining to United States persons. The prohibition extends to prevent other government agencies from sharing such commercially acquired data with intelligence or law enforcement entities, and any evidence obtained in violation of these rules is deemed inadmissible in legal proceedings. Moreover, the bill mandates that governmental entities obtain a court order, applying the most stringent legal standards, to compel disclosure of covered records from third parties. It explicitly establishes FISA as the exclusive legal means for acquiring electronic surveillance, communications records, location information, web browsing history, internet search history of United States persons, and any Fourth Amendment-protected information for foreign intelligence purposes within the United States or from United States entities. Finally, it limits civil immunity for service providers who assist the government in emergency situations without a court order, if that order is not subsequently obtained within a specified timeframe.