③ Divided Democratic Party

As Republican Party progressed satisfactorily, Truman’s candidacy had two critical challenges at that time.

In January 1948, Truman's former secretary of commerce (and vice president during Roosevelt's third term), Henry Wallace, announced his intention to run for President as a member of the Progressive Party. In September 1946, Secretary Wallace had delivered a speech critical of the administration's increasingly hard-line foreign policy towards the Soviet Union. Truman asked for Wallace's resignation, which he received. As a third-party candidate, Wallace, who for many years had been darling of the left-wing of the Democratic Party, threatened to rob Truman of the progressive vote.

Another problem was that because Truman presented a proposal to the Congress that would guarantee the rights of blacks, the entire Mississippi delegation and half of the Alabama delegation walked out at the Democratic Party convention held in Philadelphia on July 12, 1948. The southerners that remained did so only to vote against Truman's nomination. By the end of July, southern Democrats had formed the States Rights' Party (also known as the Dixiecrats). It nominated Governor J. Strom Thurmond (SC) and Governor Fielding Wright (MS) for President and vice president.

Divisions within the Democratic Party hurt Truman's chances for re-election in 1948. Truman's weakness as a candidate led some Democrats to consider offering the party's nomination to General Dwight D. Eisenhower, whom they (incorrectly) believed to be a Democrat. However, on the eve of the Democratic convention, Eisenhower strongly denied any interest in the nomination, much to Truman's relief.