National Security Act (1947)

Congressional act that reorganized the structure of the U.S. armed forces following World War II. The National Security Act created the office of secretary of defense to oversee the nation's military establishment, as well as separate departments for each branch of the armed forces. It also provided for the coordination of the military with other departments and agencies of the government concerned with national security.

The stated goal of the National Security Act was “to provide a comprehensive program for the future security of the United States” and “to provide for the establishment of integrated policies and procedures for the departments, agencies, and functions of the Government relating to national security.” To accomplish these goals, the act made several organizational changes. It replaced the former Department of War with a Department of Defense (DoD), and included the departments of the Army, Air Force, and Navy (which also included the U.S. Marine Corps) under the DoD. The reorganization was intended to create a clear and direct line of command for all military services, to eliminate the duplication of effort in the DoD (particularly in the fields of research and engineering), to provide more efficient and economical administration in the defense establishment, to provide unified strategic direction for the armed forces, and to facilitate the operation of the military under unified command—but not to establish a single chief of staff over the armed forces nor an overall armed forces general staff. However, the act did establish the Joint Chiefs of Staff (JCS) to advise the president on military strategy and planning.

The National Security Act placed a tremendous amount of emphasis on the coordination of national security with the intelligence community and its many capabilities. Most notably, the legislation created the Central Intelligence Agency (CIA) and established the position of director of central intelligence, which was charged with managing the CIA as well as overseeing the entire intelligence community. As specified in the National Security Act, the intelligence community included not only the CIA but also the National Security Agency (NSA), the Defense Intelligence Agency (DIA), and the National Reconnaissance Office, along with other intelligence and reconnaissance-related offices within the DoD and the individual services.

The National Security Act also established the National Security Council (NSC) to assist in the coordination of the nation's security assets. The NSC includes the president, vice-president, the president's national security advisor, the secretary of state, the secretary of defense, and other presidential appointees approved by the Senate. The NSC also manages smaller subcommittees to address threats to national security.