Passage of the National Security Act of 1947

The passage of the National Security Act of 1947 on July 25, 1947, marked a sweeping reorganization of power in Washington. Harry S. Truman had sought a unified military structure since taking office; the act brought the armed services under a single Department of Defense and Secretary of Defense while establishing new institutions for national security and intelligence.

Background and Purpose

Truman had sent the legislation to Congress in February. Its primary purpose was to unify the armed services under one department and one secretary, a goal he had pursued since becoming president. That institutional project also reflected his broader conviction that the war effort and its consequences required firm civilian direction, rather than leaving decisions about national power to military leaders alone.

Passage and Institutional Changes

Congress passed the act on July 25. It established the Department of Defense under a single Secretary of Defense, created the Air Force as a separate military service, set up the National Security Council, and formally authorized the Central Intelligence Agency. These provisions changed the structure of the federal government, bringing military services into a unified department while creating a council for national-security policy and providing formal authorization for a central intelligence agency.

The Act on July 25

The passage coincided with an urgent family crisis. Truman was preparing to leave for his mother, who had pneumonia, but still wanted the act passed and James V. Forrestal named Secretary of Defense before Congress recessed. At the airport, he held his departure beside the plane for nearly an hour while he waited for the remaining congressional signatures and for the bill to be brought to him. The plane took off minutes later. His attention to the legislation amid that personal emergency underscores how closely he linked the new institutional framework to the work of his presidency.