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Why doesn’t the U.S. have a Department of War anymore?
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President Harry S. Truman sits at his desk signing the National Security Act of 1947, with men in military uniforms and suits standing behind him.
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National Security Act of 1947
National Security Act of 1947 U.S. Pres. Harry S. Truman signing the National Security Act of 1947.

Why doesn’t the U.S. have a Department of War anymore?

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History

U.S. Pres. Donald Trump has signed an executive order rebranding the Department of Defense as the Department of War. The president can’t unilaterally make this decision, but it wouldn’t be the first time that the country had a Department of War.

On August 7, 1789, Pres. George Washington signed into law “An Act to establish the Executive Department to be denominated the Department of War.” Initially, the head of this department was tasked with all matters “relative to military commissions, or to the land or naval forces, ships, or warlike stores of the United States, or to such other matters respecting military or naval affairs.” With the likelihood of a naval conflict with France increasing in the wake of the XYZ Affair, an independent Department of the Navy was created on April 30, 1798. For almost the next century and a half, the War Department was essentially the United States Army.

One of the lessons of World War II was that the army and the navy often had competing or conflicting agendas, so the cabinet post of secretary of defense was established by the National Security Act of 1947 to provide overall direction for the service branches without destroying their individual identities. The War Department (the U.S. Army), the Department of the Navy, and the newly created United States Air Force (previously a component of the army as the U.S. Army Air Forces) were all gathered under the umbrella of the National Military Establishment. An amendment to the National Security Act in 1949 increased the power of the secretary of defense at the expense of the civilian service chiefs; the secretaries of the army, navy, and air force were reduced from cabinet rank and placed under the secretary of defense. At the same time, the National Military Establishment was renamed the Department of Defense.

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Michael Ray.