A dark horse candidate was a term coined in the 19th century to refer to a candidate nominated after multiple ballots at a political party's nominating convention.
The first dark horse candidate in American politics was James K. Polk, who became the nominee of the Democratic Party's convention in 1844 after delegates voted numerous times and the anticipated favorites, including former president Martin Van Buren, could not prevail.
The Origin of the Term "Dark Horse"
The phrase "dark horse" actually derives from horse racing. The most reliable explanation of the term is that trainers and jockeys would sometimes endeavor to keep a very fast horse from public view.
By training the horse "in the dark" they could enter it in a race and place bets at very favorable odds. If the horse won, the betting payoff would thus be maximized.
The British novelist Benjamin Disraeli, who would eventually turn to politics and become prime minister, used the term in its original horse-racing usage in the novel The Young Duke:
"The first favorite was never heard of, the second favorite was never seen after the distance post, all the ten-to-oners were in the race, and a dark horse which had never been thought of rushed past the grandstand in sweeping triumph."
James K. Polk, The First Dark Horse Candidate
The first dark horse candidate to receive a party nomination was James K. Polk, who emerged from relative obscurity to become the nominee of the Democratic Party at its convention in 1844.
Polk, who had served 14 years as a congressman from Tennessee, including a two-year term as speaker of the house, was not even supposed to be nominated at the convention held in Baltimore in late May 1844. The Democrats were expected to nominate Martin Van Buren, who had served one term as president in the late 1830s before losing the 1840 election to the Whig candidate, William Henry Harrison.
During the first few ballots at the 1844 convention a stalemate developed between Van Buren and Lewis Cass, an experienced politician from Michigan. Neither man could get the required two-thirds majority necessary to win the nomination.
On the eighth ballot taken at the convention, on May 28, 1844, Polk was suggested as a compromise candidate. Polk received 44 votes, Van Buren 104, and Cass 114. Finally, on the ninth ballot there was a stampede for Polk when the New York delegation abandoned hopes for another term for Van Buren, a New Yorker, and voted for Polk. Other state delegations followed, and Polk won the nomination.
Polk, who was home in Tennessee, would not know for certain that he had been nominated until a week later.
The Dark Horse Polk Caused Outrage
The day after Polk was nominated, the convention nominated Silas Wright, a senator from New York, as the vice presidential candidate. In a test of a new invention, the telegraph, Samuel F.B. Morse, had strung wire from the convention hall in Baltimore to the Capitol in Washington, 40 miles away.
When Silas Wright was nominated, the news was flashed to the Capitol. Wright, upon hearing it, was outraged. A close ally of Van Buren, he considered the nomination of Polk to be a grave insult and betrayal, and he instructed the telegraph operator in the Capitol to send back a message refusing the nomination.
The convention received Wright's message and did not believe it. After a request for confirmation was sent, Wright and the convention passed four messages back and forth. Wright finally sent two congressmen in a wagon to Baltimore to tell the convention emphatically that he would not accept the nomination as vice president.
Polk's running mate wound up being George M. Dallas of Pennsylvania.
The Dark Horse Candidate Was Mocked, But Won the Election
Reaction to Polk's nomination tended to be surprise. Henry Clay, who had already been nominated as the candidate of the Whig Party, asked, "Are our Democratic friends serious in the nominations they have made at Baltimore?"
Whig Party newspapers mocked Polk, printing headlines asking who he was. But despite the mockery, Polk won the election of 1844. The dark horse had triumphed.