In 1940, his continuing interest in aviation led Lovett, who had traveled extensively in Europe, to tour American aircraft factories and submit to Robert P. Patterson, the new secretary of the army, a report highlighting their inability to produce aircraft in the vast quantities modern warfare demanded. After reading this report, Patterson promptly made Lovett his assistant, and four months later, Secretary of War Henry L. Stimson made him assistant secretary of war for air. Lovett then supervised the immense World War II buildup of U.S. airpower. He also helped the Army Air Forces to retain some autonomy, facilitating its subsequent evolution into an independent service after the war.
Following World War II, Lovett served as undersecretary of state under George C. Marshall from 1947 to late 1948, supervising the evolving Marshall Plan and North Atlantic Treaty Organization. In September 1950, during the Korean War, he became undersecretary of defense, succeeding Marshall as secretary in late 1951. Lovett left office in 1953, but successive presidents repeatedly consulted him on assorted foreign policy issues, regarding him as one of the key "Wise Men," the establishment figures who presided over the mid-twentieth-century expansion of American international power. Lovett died in Locust Valley, Long Island, New York, on 7 May 1986.
Fanton, Jonathan. "Robert A. Lovett: The War Years." Ph.D. diss., Yale University, 1978.; Isaacson, Walter, and Evan Thomas. The Wise Men: Six Friends and the World They Made. New York: Simon and Schuster, 1986.; Sherry, Michael S. The Rise of American Air Power: The Creation of Armageddon. New Haven, CT: Yale University Press, 1987.