Senator and future President of the United States Harry S. Truman, who was first elected in 1934, decided to seek re-election to a second term.

Tom Pendergast was ill and imprisoned for widespread voter fraud in the 1936 elections, in which more votes were tallied in Kansas City than its entire population.

As such, Truman's connections to Pendergast going back to his 1922 candidacy for judge in Jackson County were a liability in the campaign.

Missouri Governor Lloyd C. Stark, who had portrayed himself as an opponent of the machine, challenged Truman for the Democratic nomination for U.S.

[1][2] Truman, who had decided to seek a second term in February 1940, overcame his Pendergast connections as well as a substantial financial deficit, defeating Stark for the Democratic nomination.