Institutions of Impact: A closer look at the U.S. Department of Defense

Editor’s note: This is the final article in a series of profiles exploring the history, mission and essential services provided by key government agencies. President-elect Donald Trump’s proposed funding cuts and potential changes to the way agencies operate could significantly weaken or otherwise alter these agencies and disrupt essential services that millions rely on daily.

The full extent of President-elect Donald Trump’s plans for the U.S. Department of Defense is not yet known, but Trump and his Cabinet pick have proposed changes to the military. Those changes could include eliminating combat roles for women and reinstating a ban on transgender people serving that was implemented in 2019 and overturned in 2021.

The Trump administration is also likely to support efforts some in Congress have made to eliminate or restrict Department of Defense diversity, inclusion and equity initiatives and, perhaps, efforts to reverse progress made addressing white supremacy and extremism in the military.

Trump has also vowed to change the name of at least one military base — Fort Liberty near Fayetteville, North Carolina — back to its previous name honoring a Confederate general. All nine Army bases — and hundreds of other ships and military installation buildings and streets — previously named for Confederate leaders were changed during the Biden administration.

History

The Department of Defense is the country’s oldest and largest government agency, with roots extending to pre-Revolutionary times, according to its website. Congress established the War Department at the Cabinet level in 1789 to oversee the operation and maintenance of the Army, Navy and Marine Corps. The department opened its official headquarters at the Pentagon in 1943 after 16 months of construction. In 1949, the National Security Act was amended, renaming the National Military Establishment to the Department of Defense. The change rescinded the Cabinet-level statuses of Army, Navy and Air Force secretaries and made them all subordinate to the secretary of defense, whose authority and responsibilities increased.

Key functions and services

The department operates with a $841.4 billion budget, employs 3.4 million service members and civilians and is responsible for 4,800 sites in more than 160 countries. The armed forces operating under the department are the Army, Marine Corps, Navy, Air Force, Space Force and Coast Guard. The Army National Guard and the Air National Guard are reserve components of their services and operate in part under state authority. The department also contains noncombat agencies including the National Security Agency, the Defense Intelligence Agency and others.

Also in the series: The Department of Justice

Illustration at top by the SPLC.