After his 1946 re-election victory, Warren began planning a run for president in the 1948 election. The two front-runners for the nomination were Dewey and Robert Taft, but Warren, Harold Stassen, Arthur Vandenberg, and General Douglas MacArthur each had significant support. Prior to the 1948 Republican National Convention, Warren attempted to position himself as a dark horse candidate who might emerge as a compromise nominee. However, Dewey won the nomination on the third ballot of the convention. Dewey once again asked Warren to serve as his running mate, and this time Warren agreed. Far ahead in the polls against President Harry S. Truman, the Democratic nominee, Dewey ran a cautious campaign that largely focused on platitudes rather than issues. Warren campaigned across the country on behalf of the ticket, but was frustrated by his inability to support specific policies. To the surprise of many observers, Truman won the election, and this became the only election Warren ever lost.