Department of Defense or Department of War: Which is it?
The DOD’s new secondary title is a callback to the agency’s original name.
On September 5, 2025, President Trump introduced “Department of War” as a secondary title for the Department of Defense in an executive order. Is the "Department of War” the new department name?
Yes and no: the DOD can use “Department of War” as a secondary title, but Congress would need to pass legislation to officially change an agency’s name. And while an act formalizing the name change has been introduced to Congress, it hasn’t passed the House or the Senate. So it’s still officially the Department of Defense under the Federal Register and on USA.gov, but the DOD does refer to itself using the secondary title, the “Department of War.”
The DOD may use ‘Department of War’ informally, but changing its official name requires an act of Congress.
A formal name change could also come with a price tag: the Government Accountability Organization estimates that it could cost anywhere from $10 million to $125 million, depending on how quickly and comprehensively the name change is implemented. Costs would include new signage, ceremonial awards, name badges, letterhead, and an updated online presence.
Why was the Department of Defense renamed?
The executive order stated that “Department of War” name “conveys a stronger message of readiness and resolve compared to ‘Department of Defense.’”
The Department of Defense’s name was actually originally the “Department of War” when it was first established in 1789 to manage the Army, Navy, and Marine Corps. When the previously independent Air Force was brought under the military umbrella after World War II, the Department of War became the National Military Establishment. In 1949, it became the “Department of Defense.”
The Department of Defense's official name, over time.
Have other agency names changed before?
Yes, during periods of reorganization or consolidation. The United States Government Manual details 215 instances of renamed agencies since 1933, and some agencies have changed more than once.
When the Department of Education Organization Act was signed into law in 1979, it separated what was then the Department of Health, Education, and Welfare into two distinct entities: the Department of Education and the Department of Health and Human Services.
US Citizenship and Immigration Services has had multiple names and been housed under multiple agencies prior to becoming USCIS in 2003. More recently, in 2014, the Government Printing Office was renamed the “Government Publishing Office.”
Learn more about the Department of Defense’s federal budget, and get data straight to your inbox by signing up for our weekly newsletter.
