The US Joint Chiefs of Staff (JCS) committee was the principal US inter-service body which, together with the British Chiefs of Staff, formed the Combined Chiefs of Staff committee, the supreme Anglo- American military strategic and operational authority, 1942-1945. With the formation of the Combined Chiefs of Staff (CCS) in Dec 1941 it became necessary to form an American agency with comparable decision making structure to that of the British Chiefs of Staff (COS). This was formally inaugurated in Feb 1942 as the Joint Chiefs of Staff (JCS) committee, its first members being Gen George Catlett Marshall, US Army Chief of Staff, Adm Harold Raynsford Stark and Adm Ernest Joseph King, US Navy, and Lt Gen Henry H 'Hap' Arnold, US Army Air Forces. In Jul 1942, President Franklin Delano Roosevelt appointed Adm William D Leahy as his political and military representative and Chief of Staff of the Joint Chiefs of Staff committee. Unlike the British Chiefs of Staff (COS), which was integrated into the British Cabinet system, the US Joint Chiefs of Staff was responsible primarily to the President of the United States as Commander-in-Chief of the US Armed Forces. Under Leahy's leadership, the Joint Chiefs of Staff became the centre of the US executive command structure during World War Two and was responsible for operational strategy in the Pacific, the co-ordination of US military operations in the Far East, and the planning and co-ordination of US operational strategy elsewhere. In addition, the US Joint Chiefs of Staff and the British Chiefs of Staff functioned together under the auspices of the Combined Chiefs of Staff to plan Allied strategic and operational efforts in Europe, North Africa, and the Far East.
From the guide to the Records of the Joint Chiefs of Staff, part 1: 1942-1945, 1942-1945, 1980-1981, (King's College London, Liddell Hart Centre for Military Archives)
