Truman had acceded to the presidency in April 1945 after the death of Franklin D. Roosevelt . Defeating attempts to drop him from the ticket , Truman won the presidential nomination at the 1948 Democratic National Convention . The Democratic convention 's civil rights plank caused a walk-out by several Southern delegates , who launched a third-party " Dixiecrat " ticket led by Governor Strom Thurmond of South Carolina . 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 . Truman also faced a challenge from the left in the form of former Vice President Henry A. Wallace , who launched the Progressive Party and challenged Truman 's confrontational Cold War policies . Dewey , who was the leader of his party 's moderate eastern wing and had been the 1944 Republican presidential nominee , defeated Senator Robert A. Taft and other challengers at the 1948 Republican National Convention
1948 Republican National Convention
1948 Republican National Convention
1948 United States presidential election