The term “dark horse candidate” is used to describe a minor candidate or party figure who was not originally considered but who steps in as a compromise choice. A dark horse, in betting parlance, is not among the betting favorites. The first dark horse candidate to win nomination was Tennessee politician James K. Polk, who emerged from the Democratic Convention of 1844 and went on to win the presidency. The opposition Whig Party had used the slogan, “Who is James K. Polk?”

Other dark horse candidates in history include: New Hampshire politician Franklin Pierce, New York politician Horatio Seymour, Ohio governor Rutherford B. Hayes, U.S. representative James A. Garfield of Ohio, U.S. senator Warren G. Harding of Ohio, and former U.S. representative John W. Davis of West Virginia. Of these, Pierce, Hayes, Garfield, and Harding were elected president.