How the Department of War became the Department of Defense

Driving the news: Trump is expected to sign an executive order Friday making the "Department of War" a secondary title for Department of Defense officials.

• This would give Defense Secretary Pete Hegseth and his subordinates secondary titles such as "Secretary of War" and "Deputy Secretary of War," a White House official previously told Axios.
• The move is seen by many as the Trump administration's way of instilling a "warrior ethos" in the military under Hegseth.

Reality check: Changing the name officially would require an act of Congress. Republicans introduced a bill Friday — titled the "Department of War Restoration Act of 2025" — that would do just that.

Yes, but: America's military has cycled through many names in the last 250 years.

Here's a look at the history of the Defense Department's name.

Department of War origins

Flashback: Congress established the War Department in 1789 to oversee the Army, Navy and Marine Corps, according to the department's website.

• It originally came with one Cabinet-level role. Revolutionary War Commander Henry Knox served as the first secretary.
• In 1798, a new Navy Department was created after "tensions with France prompted greater public support for a strong navy," according to the Defense Department.

Fun fact: An Army Seal once had the phrase "War Office" written on it, which referred to the Army's headquarters.

The National Military Establishment

After World War II in 1947, President Harry Truman merged the Navy and War Departments, as well as the Air Force, into a single National Military Establishment through the National Security Act.

• The department was led by a secretary of defense who also managed the Joint Chiefs of Staff, per the Defense Department website.
• The War Department and Navy Department each had a Cabinet-level secretary, reporting directly to the president. The act also created the Department of the Air Force, which was led by its own secretary.

• The act signed by Truman also created the CIA, the National Security Agency and the National Security Resources Board.

Department of Defense debuts

About two years later, the National Security Act was amended and the National Military Establishment was renamed the Department of Defense.

• The change removed Cabinet-level positions for the Army, Navy and Air Force secretaries, which were replaced by the Secretary of Defense.
• The move also established a chairman of the Joint Chiefs of Staff.

Department of War

What's next: The White House has been aggressively pushing to rename the department again, with the Department of War as the new name. Hegseth has reportedly renamed his Pentagon conference room as the "W.A.R. Room."

What they're saying: "As Department of War, we won everything. We won everything," Trump said last month. "I think we're going to have to go back to that."

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