500
The National Defense Act of 1947 created this government office.
The Act merged the Department of War and the Department of the Navy into the National Military Establishment, headed by the Secretary of Defense. It was also responsible for the creation of a separate Department of the Air Force from the existing Army Air Forces. Initially, each of the three service secretaries maintained quasi-cabinet status, but the act was amended on August 10, 1949, to assure their subordination to the Secretary of Defense. At the same time, the NME was renamed as the Department of Defense. The purpose was to unify the Army, Navy, and what was soon to become the Air Force into a federated structure. The Act officially established the Joint Chiefs of Staff.