National Security Act of 1947 U.S. Pres. Harry S. Truman signing the National Security Act of 1947. (more) Why doesn’t the U.S. have a Department of War anymore? Ask the Chatbot a Question More Actions Share Share Share to social media Facebook X URL https://www.britannica.com/topic/Why-doesnt-the-US-have-a-Department-of-War-anymore Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.

　　External Websites Ask the Chatbot a Question Written by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... The Editors of Encyclopaedia Britannica Last Updated: Sep 5, 2025 • Article History Table of Contents Table of Contents Ask the Chatbot On June 27, 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 ...(100 of 263 words)

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