Except that it is absolutely called The Department of War and that's by Trump's own hand.

https://www.whitehouse.gov/presidential-actions/2025/09/rest...

"By the authority vested in me as President by the Constitution and the laws of the United States of America, it is hereby ordered:

"The name “Department of War,” more than the current “Department of Defense,” ensures peace through strength, as it demonstrates our ability and willingness to fight and win wars on behalf of our Nation at a moment’s notice, not just to defend. This name sharpens the Department’s focus on our own national interest and our adversaries’ focus on our willingness and availability to wage war to secure what is ours. I have therefore determined that this Department should once again be known as the Department of War and the Secretary should be known as the Secretary of War."