If the Electoral College ends in a tie, or if no candidate reaches 270 electoral votes for any other reason, the presidential election moves to Congress under the 12th Amendment. The House of Representatives chooses the President, voting by state delegation, and the Senate chooses the Vice President. This backup procedure is called a contingent election.1Library of Congress. U.S. Constitution – Twelfth Amendment
What Triggers the Backup Procedure
There are 538 electors, and the 12th Amendment requires “a majority of the whole number of Electors appointed” to win outright.1Library of Congress. U.S. Constitution – Twelfth Amendment That majority is 270.2National Archives. What is the Electoral College? Fall one vote short and the contingent election process begins.
A perfect 269-269 split is the cleanest path there, but it isn’t the only one. A third-party or independent candidate who carries even a state or two could pull enough electors away from both major-party candidates that neither reaches 270. Any three-way split that leaves no one with a majority sends the decision to Congress the same way a tie would.
How the House Picks the President
This is nothing like a normal House vote. Each state delegation gets a single vote, no matter how many representatives it has. Wyoming’s lone member carries the same weight as California’s 52. The House chooses among the three candidates who received the most electoral votes.1Library of Congress. U.S. Constitution – Twelfth Amendment
The vote is held by the incoming Congress, not the outgoing one. Under the 20th Amendment, new members are sworn in on January 3, and the electoral votes are counted on January 6. The partisan makeup of the new delegations is what counts, and it can differ from the Congress that just left.
How a State Casts Its One Vote
Inside each delegation, the representatives hold their own vote to decide which candidate gets the state’s ballot. A simple majority wins it. If a delegation splits evenly, the state is recorded as “divided” and casts no vote at all. To become President, a candidate needs a majority of the states, meaning at least 26. The House keeps balloting in successive rounds until someone gets there. The Constitution sets no deadline, but the inauguration calendar creates intense pressure to finish.
Quorum, and Why D.C. Is Left Out
Before any balloting can happen, at least one representative from two-thirds of the states, or 34 states, must be present to form a quorum.1Library of Congress. U.S. Constitution – Twelfth Amendment
The District of Columbia has no role here. The 23rd Amendment gives D.C. residents three electoral votes in the general election, but D.C. is not a state and has no voting representation in the House, so its residents have no voice in a contingent election.
How the Senate Picks the Vice President
The Senate runs its own contingent election at the same time, and the process is simpler. Each of the 100 senators casts an individual vote, choosing between the two vice-presidential candidates who received the most electoral votes. A candidate needs 51 votes to win.1Library of Congress. U.S. Constitution – Twelfth Amendment The quorum requirement is two-thirds of the Senate, or 67 senators.
Because the two chambers act independently, nothing keeps the results in sync. A President and Vice President from different parties could be elected, and the political dynamics in each chamber can pull the outcomes apart.
If Nobody Is Chosen by January 20
The 20th Amendment builds in a safety net. If the House is still deadlocked on Inauguration Day at noon and the Senate has picked a Vice President, the Vice President-elect becomes Acting President until the House finally settles on someone.3Constitution Annotated. U.S. Constitution – Twentieth Amendment
If neither chamber has chosen anyone by then, the Presidential Succession Act takes over. The Speaker of the House becomes Acting President, but only after resigning both as Speaker and as a member of Congress.4Office of the Law Revision Counsel. 3 USC 19 – Vacancy in Offices of Both President and Vice President; Officers Eligible to Act If there is no Speaker, or the Speaker declines, the President pro tempore of the Senate is next in line under the same resignation rule.
Whoever serves as Acting President in this situation holds the job only until a President or Vice President is finally chosen and qualifies. The House can keep balloting past January 20, and the Acting President steps aside the moment it picks a winner.4Office of the Law Revision Counsel. 3 USC 19 – Vacancy in Offices of Both President and Vice President; Officers Eligible to Act
Has This Ever Actually Happened
Contingent elections are not purely theoretical, though a modern 269-269 tie has never occurred. The House has resolved a presidential election twice, and the Senate has chosen a Vice President once.
In 1800, before the 12th Amendment existed, Thomas Jefferson and Aaron Burr each received 73 electoral votes. The House took 36 ballots over roughly a week before electing Jefferson. That episode led directly to the 12th Amendment in 1804, which required electors to vote separately for President and Vice President.
The only contingent presidential election under the 12th Amendment came in 1824, when Andrew Jackson, John Quincy Adams, William Crawford, and Henry Clay split the electoral vote and none reached a majority. With only the top three eligible, Clay was dropped, and the House chose Adams on the first ballot on February 9, 1825, even though Jackson had led in both electoral and popular votes.
The Senate’s only vice-presidential contingent election followed the 1836 election. Richard Mentor Johnson finished one electoral vote short of a majority after Virginia’s electors refused to back him. The Senate picked him over Francis Granger by a 33 to 17 vote.