"[324] Roosevelt realized that his declining health could eventually make it impossible for him to continue as president, and in 1945 he told a confidant that he might resign from the presidency following the end of the war.[325]

Election of 1944
Main articles: 1944 United States presidential election and 1944 Democratic Party vice presidential candidate selection
1944 electoral vote results
While some Democrats had opposed Roosevelt's nomination in 1940, the president faced little difficulty in securing his re-nomination at the 1944 Democratic National Convention. Roosevelt made it clear before the convention that he was seeking another term, and on the lone presidential ballot of the convention, Roosevelt won the vast majority of delegates, although a minority of Southern Democrats voted for Harry F. Byrd. Party leaders prevailed upon Roosevelt to drop Vice President Wallace from the ticket, believing him to be an electoral liability and a poor potential successor in case of Roosevelt's death. Roosevelt preferred Byrnes as Wallace's replacement but was convinced to support Senator Harry S. Truman of Missouri, who had earned renown for his investigation of war production inefficiency and was acceptable to the various factions of the party. 