Truman had known of the Manhattan Project’s existence since his wartime Senate work as chairman of the Committee to Investigate the National Defense Program, when he had attempted to explore the expensive secret project’s purpose and had been rebuffed by the Secretary of War himself. That a senator of watchdog responsibility and bulldog tenacity would call off an investigation into unaccounted millions of dollars in defense-plant construction on Stimson’s word alone gives some measure of the quality of the Secretary’s reputation.
