The contingent election procedure, along with the other parts of the presidential election process, was first established in Article Two, Section 1, Clause 3 of the United States Constitution, and then modified by the 12th Amendment in 1804. During a contingent election, each House state delegation casts one en bloc vote to determine the president, rather than a vote for each representative. Senators instead cast votes individually for vice president.

Contingent elections are extremely rare, having occurred only three times in American history, all in the early 1800s. In 1800, Thomas Jefferson was pitted against his own vice-presidential nominee in a contingent election due to problems with the original electoral procedure. In 1824, the presence of four candidates split the Electoral College, and Andrew Jackson lost the contingent election to John Quincy Adams despite winning a plurality of both the popular and electoral vote. In 1836, faithless electors in Virginia refused to vote for Martin Van Buren's vice-presidential nominee Richard Mentor Johnson, denying him a majority of the electoral vote and forcing the Senate to elect him in a contingent election.

All three contingent elections in the 1800s were held by the outgoing Congress, as, at the time, congressional terms ended/began on the same day as presidential terms. In the event of a future Electoral College deadlock regarding either the presidential election or the vice presidential election, it will be the incoming Congress holding a contingent election. This is because the 1933 20th Amendment changed it so that congressional terms now end/begin before presidential and vice presidential terms do.