S. 758, An Act to promote the national security by providing for a National Security Organization . . . (National Security Act), July 15, 1947
It took three years of sometimes contentious debate for Congress to enact the National Security Act of 1947. Support for unification of the military establishment initially was slim, as Congress had concerns over the concentration of too much power in the hands of too few and reduced congressional control over the military. Interservice disputes over strategic and command issues also slowed the bill’s progress.
Records of the U.S. House of Representatives, National Archives and Records Administration
The National Security Act
In the aftermath of World War II, Congress passed legislation to modernize the U.S. military and intelligence communities. Known as the National Security Act of 1947, the act merged the Army, Navy, and newly created Air Force into a unified National Military Establishment headed by a secretary of defense. It also created the National Security Council, the Central Intelligence Agency, and the Joint Chiefs of Staff. By approving the act, Congress established an institution to coordinate U.S. defense policy throughout the Cold War era.
The experiences of the war just concluded have proven conclusively that we must maintain in time of peace an adequate organization of the national defense readily available to the needs of war on short notice.
National Security Act of 1947, House Report 80-961, 1947