(Saturday, July 26, 1947, 12:15 p.m. EDT; during the Cold War) — President Harry S. Truman today (aboard his VC-54C presidential aircraft Sacred Cow, the first aircraft used for the role of Air Force One) signed the National Security Act of 1947, which merged the Department of War (renamed as the Department of the Army) and the Department of the Navy into the National Military Establishment (NME), headed by the Secretary of Defense.

It also created the Department of the Air Force and the United States Air Force, which separated the Army Air Forces into its own service. It also protected the Marine Corps as an independent service, under the Department of the Navy.

Aside from the military reorganization, the act established the National Security Council and the Central Intelligence Agency, the U.S.’s first peacetime non-military intelligence agency.