On 9 March 1942 the Army Service Forces (ASF), the Army Ground Forces (AGF), and the Army Air Forces (AAF) came into being as the three major commands within the United States to do the work of the War Department. The Army Service Forces was a unique organization, although it was in part modeled after the
Services of Supply (SOS) that had been set up in France as a separate command within the American Expeditionary Forces (AEF) of Gen. John J. Pershing. There was no exact counterpart to it within the United States during World War I. When General Pershing became Chief of Staff of the Army in 1921 and reconstructed the War Department General Staff (WDGS), he did not provide for a Services of Supply. It was not until two months after the Japanese attack on Pearl Harbor that Gen. George C. Marshall, Chief of Staff, and Secretary of War Henry L. Stimson decided on a new organization for the War Department and the Army.