The 1948 presidential election was one of the most dramatic in U.S. history. Incumbent Harry Truman (who had assumed the office when President Franklin D. Roosevelt died on April 12, 1945) won in a huge upset.

Public opinion polling was in its infancy, but nevertheless all the polls and most prognosticators predicted that Governor Thomas Dewey of New York would win easily. But the majority of voters chose Truman.

Truman had not been a popular president. The economy at the end of World War II went through some tough times readjusting to a peacetime era. Some people thought that the tough-talkin...