> Defense was always just a euphemism for War. That’s not the signal you think it is.

No, it was not. Tom Nichols, professor emiritus of national-security affairs at the U.S. Naval War College:

> It is almost impossible to overstate the inanity of this move. The United States has a Department of Defense for a reason. It was called the “War” Department until 1947, when the dictates of a new and more dangerous world required the creation of a much larger military organization than any in American history. Harry Truman and the American leaders who destroyed the Axis, and who now were facing the Soviet empire, realized that national security had become a larger undertaking than the previous American tradition of moving, as needed, between discrete conditions of “war” and “peace.”

> These leaders understood that America could no longer afford the isolationist luxury of militarizing itself during times of threat and then making soldiers train with wooden sticks[1] when the storm clouds passed. Now, they knew, the security of the country would be a daily undertaking, a matter of ongoing national defense, in which the actual exercise of military force would be only part of preserving the freedom and independence of the United States and its allies.

> In 1949, after two years that included a massive reorganization of the U.S. military (and the establishment of an air force), Truman christened the new United States Department of Defense, which consolidated elements of the previous War and Navy Departments. […]

* https://archive.is/https://www.theatlantic.com/ideas/archive...

The Department of War had a different function for a different geopolitical outlook that no longer matched reality in the post-WW2 world.

Why isn't it? The change was clearly made to indicate the posture of the department. Either to US citizens or to powers abroad. Even though its "just" words it indicates intent.

If they have identical meanings then why’d they change it?