The National Security Act is an American federal law voted the July 26th 1947 entered in strength the September 18th 1947.

The Congrès of the United States decided the realignment and the reorganization of the armed forces, the American Diplomatie and the community of the information in this whole beginning of Cold war. It creates in particular the safety advice main road, the United States Air Force and for the first time in times of peace, an agency of Renseignement, the Central Intelligence Agency.