National defense was critical on the eve of World War II. Congress worried about possible waste and mismanagement in military preparations, and wanted to ensure that defense dollars were spent wisely. Senator Harry Truman of Missouri chaired a Special Committee to Investigate the National Defense Program (popularly called the Truman Committee).

Truman Committee hearings exposed abuses while encouraging industry, labor, and government to cooperate. Though scrutinizing military matters, the committee avoided interfering in military strategy. Truman’s tireless investigations won praise for improving defense production and saving millions of dollars. They also won Truman national attention—and the 1944 Democratic nomination as vice president. Truman became president in 1945, after Franklin D. Roosevelt’s death. His committee, meanwhile, continued after the war as the Senate’s Permanent Subcommittee on Investigations.

"Everyone connected with the national-defense program should have a patriotic interest in seeing that it is properly carried out."
— Senator Harry Truman of Missouri, February 10, 1941