The Crack of Dawn #80-I forget

11/18/2025

The U.S. Department of War was renamed the Department of Defense on August 10, 1949, through amendments to the National Security Act of 1947.

The path to this name change began with the original National Security Act, which President Harry S. Truman signed into law on July 26, 1947. This act created a new executive department called the National Military Establishment (NME) to oversee the existing Department of War and Department of the Navy, and the newly established Department of the Air Force.

However, the initial structure of the NME caused interservice rivalry because the individual service secretaries still held cabinet-level positions. To address these inefficiencies, the 1949 amendments gave the Secretary of Defense full “direction, authority, and control” over the entire organization, establishing it as a cabinet-level department and officially renaming it the Department of Defense.