National Security Act of 1947

Signed aboard an airplane

Harry S. Truman signed Public Law 80-253, the National Security Act, on 26 July 1947 aboard the presidential VC-54C aircraft Sacred Cow, immediately before departing Washington.

The law provided for a Secretary of Defense and a National Military Establishment; separate Departments of the Army, Navy and Air Force; a statutory Joint Chiefs of Staff; the National Security Council; the Central Intelligence Agency; and the National Security Resources Board.

The same day, Truman issued Executive Order 9877 assigning primary functions and responsibilities to the three armed services, and nominated James V. Forrestal as the first Secretary of Defense. The Senate confirmed Forrestal that evening.

Not yet the Department of Defense

The umbrella organization the act created was called the National Military Establishment. The name Department of Defense dates from the 1949 amendments, which also substantially strengthened the Secretary of Defense's authority.

The service departments remained separately administered, so the Secretary's initial power was limited. The Joint Chiefs of Staff, meanwhile, had functioned since 1942 without a statutory basis; the act gave them their first authority in law.

Fifty-four days before most machinery became operative

Signing the bill did not put most of the new machinery to work that afternoon. Most provisions took effect on 18 September, the day after Forrestal was sworn in on 17 September 1947.

The CIA's assigned duties were to coordinate, evaluate and disseminate intelligence. Departmental intelligence services remained independent, and the act did not centralize all intelligence collection in the new agency.