1920s and the 1930s. Officers like Smith, commissioned between November 1916 and November 1918, made up 55.6% of the Army's officer corps in 1926. Promotions were usually based on seniority, and the modest objective of promoting officers to major after 17 years of service could not be met because of a shortage of posts for them to fill. World War II Washington, DC When General George C. Marshall became the Army's Chief of Staff in September 1939, he brought Smith to Washington, D.C., to be the assistant to the secretary of the General Staff. The Secretary of the General Staff was primarily concerned with records, paperwork, and the collection of statistics, but he also performed a great deal of analysis, liaison, and administration. One of Smith's duties was liaison with Major General Edwin "Pa" Watson, the senior military aide to President Franklin D. Roosevelt. Smith was promoted to lieutenant colonel on 4 May 1941, and then to colonel on 30 August 1941. On 1 September, the Secretary of the General Staff, Colonel Orlando Ward, was given command of the 1st Armored Division, and Smith became secretary of the General Staff. The Arcadia Conference, which was held in Washington, D.C., December 1941 and January 1942, mandated the creation of the Joint Chiefs of Staff as a counterpart to the British Chiefs of Staff Committee, and Smith was named as its secretary on 23 January 1942. The same conference also brought about the creation of the Combined Chiefs of Staff, which consisted of the (American) Joint Chiefs of Staff and the (British) Chiefs of Staff Committee meeting as a single body. Brigadier Vivian Dykes of the British Joint Staff Mission provided the secretarial arrangements for the new organization at first, but Marshall thought that an American secretariat was required. He appointed Smith as the secretary of the Combined Chiefs of Staff and of the Joint Chiefs of Staff. Since Dykes was senior in service time to Smith, and Marshall wanted Smith to be in charge, Smith was promoted to brigadier general on 2 February 1942. He assumed the new post a week later, with Dykes as his deputy. The two men worked in partnership to create and organize the secretariat and to build the organization of the Combined Chiefs-of-Staff into one which could co-ordinate the war efforts of both allies, along with the Canadians, Australians, French and others. Smith's duties involved taking