Perhaps in response to such concerns, Congress established sunset provisions which apply to three of the most controversial amendments to FISA:
Section 6001(a) of the Intelligence Reform and Terrorism Prevention Act (IRTPA), also known as the "lone wolf" provision, which simplifies the evidentiary showing needed to obtain a FISA court order to target non-U.S. persons who engage in international terrorism or activities in preparation therefor, specifically by authorizing such orders in the absence of a proven link between a targeted individual and a foreign power; Section 206 of the USA PATRIOT Act, which permits multipoint, or "roving," wiretaps (i.e., wiretaps which may follow a target even when he or she changes phones) by adding flexibility to the manner in which the subject of a FISA court order is specified; and Section 215 of the USA PATRIOT Act, which authorizes orders compelling a person to produce "any tangible thing" that is "relevant" to an authorized foreign intelligence, international terrorism, or counter-espionage investigation. In summer 2013, media began reporting on several foreign intelligence activities conducted by the National Security Agency (NSA), including the bulk collection of telephone metadata under Section 215. One day later, Congress enacted the USA FREEDOM Act, which placed new limitations on the scope of the government's foreign intelligence activities, while simultaneously extending the expired provisions through December 15, 2019. It both enlarged the scope of materials that may be sought and lowered the standard for a court to issue an order compelling their production. Roving Wiretaps

Section 206 of the USA PATRIOT Act amended FISA to permit multipoint, or "roving," wiretaps by adding flexibility to the degree of specificity with which the location or facility subject to electronic surveillance under FISA must be identified. The grandfather clauses authorize the continued effect of the amendments with respect to investigations that began, or potential offenses that took place, before the provisions' sunset date.
Two amendments to the Foreign Intelligence Surveillance Act (FISA) were enacted as part of the USA PATRIOT Act. Section 206 of the USA PATRIOT Act amended FISA to permit multipoint, or "roving," wiretaps by adding flexibility to the degree of specificity with which the location or facility subject to electronic surveillance under FISA must be identified. Section 215 enlarged the scope of materials that could be sought under FISA to include "any tangible thing." It also lowered the standard required before a court order may be issued to compel their production.
A third amendment to FISA was enacted in 2004, as part of the Intelligence Reform and Terrorism Prevention Act (IRTPA). Section 6001(a) of the IRTPA changed the rules regarding the types of individuals who may be targets of FISA-authorized searches. Also known as the "lone wolf" provision, it permits surveillance of non-U.S. persons engaged in international terrorism without requiring evidence linking those persons to an identifiable foreign power or terrorist organization.
In summer 2013, media began reporting on several foreign intelligence activities conducted by the National Security Agency (NSA), including the bulk collection of telephone metadata under Section 215 of the USA PATRIOT Act. After a one-day lapse in the expiring authorities, Congress enacted the USA FREEDOM Act, which placed new limitations on the scope of the government's foreign intelligence activities, while simultaneously extending the expired provisions through December 15, 2019.
Although these provisions are set to sunset at the end of 2019, grandfather clauses permit them to remain effective with respect to investigations that began, or potential offenses that took place, before the sunset date.