Hancock was also involved in civil affairs again. He was executive officer in the National Recovery Administration in 1933, member of the War Production Board in 1939, and assistant director in the Office of War Mobilization in 1943 appointed by President Franklin D. Roosevelt. In 1942 he had done a government survey of the rubber industry with Bernard Baruch, and in 1946 again joined him as general manager of the U.S. Delegation to the United Nations Atomic Energy Commission.
