Claim: Republican, Thomas Dewey won the 1948 presidential election in New Hampshire defeating Harry S Truman in that state, although Truman went on to win the election, having been president since he took over upon the death of Franklin D Roosevelt in 1945.
Evidence: Thomas Edmund Dewey
Republican 121,299 52.41% Harry S. Truman
Democratic 107,995 46.66% Totals In one of the greatest election upsets in American history, incumbent President Harry S. Truman, the Democratic nominee, defeated Republican Governor Thomas E. Dewey. Truman had ascended to the presidency in April 1945 after the death of Franklin D. Roosevelt.