dark horse

1. One who achieves unexpected support and success as a political candidate, typically during a party's convention.
2. A little-known, unexpectedly successful entrant, as in a horserace.

A little known, unexpectedly successful entrant, as in You never can tell--some dark horse may come along and win a Senate seat. This metaphoric expression originally alluded to an unknown horse winning a race and was so used in a novel by Benjamin Disraeli (The Young Duke, 1831). It soon began to be transferred to political candidates, among the first of whom was James K. Polk. He won the 1844 Democratic Presidential nomination on the eighth ballot and went on to win the election.

Dark Horse, a compromise candidate selected as party nominee when a deadlock arises among leading candidates. The candidate is usually substantially colorless with respect to current issues, unidentified with party factions, and unobjectionable in his public and private life. In 1844, James K. Polk became the first dark horse presidential candidate when Martin Van Buren, the expected Democratic choice, rendered himself unpopular to many in his party by arguing against the immediate annexation of Texas. In 1852, Franklin Pierce followed in the dark horse tradition. Other more recent examples of dark horses include James A. Garfield, Chester A. Arthur, and Warren G. Harding.

Bibliography

Doenecke, Justus D. The Presidencies of James A. Garfield and Chester A. Arthur. Lawrence: Regents Press of Kansas, 1981.

Gara, Larry. The Presidency of Franklin Pierce. Lawrence: University Press of Kansas, 1991.

Haynes, Sam W. James K. Polk and the Expansionist Impulse. New York: Longman, 1997.

—W. B. Hatcher/A. E.

An unexpected winner. In politics, a dark horse is a candidate for office considered unlikely to receive his or her party's nomination, but who might be nominated if party leaders cannot agree on a better candidate.

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(dark hors)

noun
Someone little-known who ends up winning a contest unexpectedly.

Etymology
From the idea of a relatively unknown horse winning a race. The term is also used for a person who unexpectedly wins a party's nomination for a political contest, often as a compromise candidate. The OED shows the first citation of the term from the novel The Young Duke by the British prime minister Benjamin Disraeli

The early convention atmosphere and a fear of deadlock among the most popular candidates (based on the Democratic Party rule that a presidential candidate needed to win two-thirds of the convention delegates to capture his party's nomination), led to the occasional selection of a "dark horse" candidate. The term 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.