In the months leading up to the opening of the 1940 Republican National Convention, the three leading candidates for the GOP nomination were considered to be Senators Robert A. Taft of Ohio and Arthur Vandenberg of Michigan, and District Attorney Thomas E. Dewey of New York.
All three men had campaigned vigorously during the primary season, but only 300 of the 1,000 convention delegates had been pledged to a candidate by the time the convention opened.