Comment by dragonwriter

There’s something in a dead reply that's a popular enough myth that its worth responding to:

> Something every single soldier and officer learns is that the entire department was previously called the Department of War. It was repackaged after WW2 as the Department of Defense when invading countries half-way around the world began being sold to the public as 'defense.'

This is a weirdly common belief, but it is not true. Up through WWII, the US had two cabinet level military departments, instead of the current one. Those two departments were the Department of War, under which was the Army, and fhe Department of the Navy, under which was the Navy and Marine Corps.

This was changed by two laws in the late 1940s. The first, the National Security Act of 1947, among other things:

* Split the Air Force and Army from each other, splitting the Department of War into two new cabinet-level Departments, the Department of the Army and the Department of the Air Force.

* Created an additional cabinet level Secretary of Defense to coordinate the combined military structure, which it called the National Military Establishment.

This was followed by the National Security Amendments Act of 1949, which:

* removed the Secretaries of the Army, Navy, and Air Force from the Cabinet and formally subordinated them to the Secretary of Defense

* renamed the National Military Establishment (which was frequently referred to by the inconveniently-pronounced, for its role, initialism NME) the Department of Defense (which conbined with the preceding point is the source of the unusual departments-within-a-department structure of the DoD.)

The Department of War did once exist, but it was never a name for the same thing as the Department of Defense. It was one of two coequal entities that were subsumed by the National Military Establishment, the only reason it still doesn't exist as a subordinate entity within the NME, now DoD, like the Department of the Navy does is that it was split in two.