In 1940 he was appointed Secretary of War again under Franklin D. Roosevelt. As War Secretary during World War II he expanded the army base to over 10,000,000 [[soldier]]s. As Secretary of War under Harry Truman he was a senior adviser to the [[Manhattan Project]], which built the [[atomic bomb]]. | In 1940 he was appointed Secretary of War again under Franklin D. Roosevelt. As War Secretary during World War II he expanded the army base to over 10,000,000 [[soldier]]s. As Secretary of War under Harry Truman he was a senior adviser to the [[Manhattan Project]], which built the [[atomic bomb]]. |