"'Gang of Four' intelligence notifications generally are oral briefings of certain particularly sensitive non-covert action intelligence activities, including principally, but not exclusively, intelligence collection programs, that the Intelligence Community typically limits to the chairmen and ranking members of the two congressional intelligence committees, and at times, but not always, to their respective staff directors. […]. This report reviews the history of Gang of Four notification process and compares this procedure with that of the 'Gang of Eight' notification procedure. The 'Gang of Eight' procedure is statutorily based and provides that that the Chairmen and Ranking Members of the intelligence committee, along with the Speaker and minority leader of the House, and Senate majority and minority leaders--rather than the full membership of the intelligence committees--are to receive prior notice of particularly sensitive covert action programs, if the President determines that limited access to such programs is essential to meet extraordinary circumstances affecting vital U.S. interests. Although the FY2010 Intelligence Authorization bills approved by the two congressional intelligence committees address Gang of Eight covert action notifications, neither of the two bills reference Gang of Four notifications. Congress has not acted on the FY2010 Intelligence Authorization bill."
CRS Report for Congress, R40698