https://www.whitehouse.gov/fact-sheets/2025/09/fact-sheet-president-donald-j-trump-restores-the-united-states-department-of-war/

tl;dr

• they called it Department of War, from 1789 to 1947

• National Military Establishment, from 1947 to 1949

• Department of Defense, from 1949 to today

• only Congress can change it officially

• but President can change it unofficially, allow alternate name for daily work

• since 1949, USA won only smallest wars - Panama, Grenada - had better fortune with old name

• old name makes purpose clear: when that department gets involved, it's war, & wars are to be won, or else don't do it

Palmer Lucky of Anduril, did he start it? He may think so. https://x.com/lulumeservey/status/1964098589631672405