Presidential elections were held in the United States on November 2, 1948. The Democratic ticket of incumbent President Harry S. Truman and Senator Alben Barkley defeated the Republican ticket of New York Governor Thomas E. Dewey and California Governor Earl Warren and the Dixiecrat ticket of South Carolina Governor Strom Thurmond and Mississippi Governor Fielding Wright in one of the greatest election upsets in American history.
Truman had been elected vice president in the 1944 election, and he succeeded to the presidency in April 1945 upon the death of Franklin D. Roosevelt. He won his party's nomination at the 1948 Democratic National Convention only after defeating attempts to drop him from the ticket. The convention's civil rights plank caused a walkout by several Southern delegates, who launched a third-party "States' Rights Democratic Party" ticket, more commonly known as the Dixiecrats, led by South Carolina Governor Strom Thurmond. The Dixiecrats hoped to win enough electoral votes to force a contingent election in the House of Representatives, where they could extract concessions from either Dewey or Truman in exchange for their support. Former vice president Henry A. Wallace also challenged Truman by launching the Progressive Party and criticizing his confrontational Cold War policies. Dewey, the leader of his party's liberal eastern wing and the 1944 Republican presidential nominee, defeated conservative Ohio Senator Robert A. Taft and other challengers at the 1948 Republican National Convention. This was the first election to have primary and general election debates, with Dewey debating Harold Stassen in the Republican primary, while Norman Thomas debated Farrell Dobbs in the general election.