military medical examination, Schlesinger joined the Office of War Information. From 1943 to 1945, he served as an intelligence analyst in the Office of Strategic Services, a precursor to the CIA. Schlesinger's service in the OSS allowed him time to complete his first Pulitzer Prize–winning book, The Age of Jackson, in 1945. From 1946 to 1954, he was an associate professor at Harvard, becoming a full professor in 1954. Political activities before 1960 In 1947, Schlesinger, together with former First Lady Eleanor Roosevelt, Minneapolis mayor and future Senator and Vice President Hubert Humphrey, economist and longtime friend John Kenneth Galbraith, and Protestant theologian Reinhold Niebuhr, founded Americans for Democratic Action. Schlesinger acted as the ADA's national chairman from 1953 to 1954. After President Harry S. Truman announced he would not run for a second full term in the 1952 presidential election, Schlesinger became the primary speechwriter for and an ardent supporter of Governor Adlai E. Stevenson of Illinois. In the 1956 election, Schlesinger, along with 30-year-old Robert F. Kennedy, again worked on Stevenson's campaign staff. Schlesinger supported the nomination of Massachusetts Senator John F. Kennedy as Stevenson's vice-presidential running mate, but at the Democratic convention, Kennedy came second in the vice-presidential balloting, losing to Senator Estes Kefauver of Tennessee. Schlesinger had known John F. Kennedy since attending Harvard and increasingly socialized with Kennedy and his wife Jacqueline in the 1950s. In 1954, The Boston Post publisher John Fox Jr. planned a series of newspaper pieces labeling several Harvard figures, including Schlesinger, as "reds"; Kennedy intervened on Schlesinger's behalf, which Schlesinger recounted in A Thousand Days. During the 1960 campaign, Schlesinger supported Kennedy, causing much consternation to Stevenson loyalists. At the time, however, Kennedy was an active candidate while Stevenson refused to run unless he was drafted at the convention. After Kennedy won the nomination, Schlesinger helped the campaign as a (sometime) speechwriter, speaker, and member of the ADA. He also wrote the book Kennedy or Nixon: Does It Make Any Difference? in which he lauded Kennedy's abilities and scorned Vice President Richard M. Nixon as having "no ideas, only methods.... He cares about winning." Kennedy administration After the election, the president-elect offered Schlesinger an ambassadorship and Assistant Secretary of State for Cultural Relations before Robert Kennedy proposed that Schlesinger serve as a "sort of roving reporter and troubleshooter." Schlesinger quickly accepted, and on January 30, 1961, he resigned from Harvard