The Twelfth Amendment, ratified in 1804 after the tie between Thomas Jefferson and Aaron Burr in 1800, provides that if no candidate wins a majority of electoral votes, now 270 of 538, the House of Representatives chooses the President from the top three electoral vote winners. Each state delegation casts a single vote, so Wyoming counts as much as California, and a candidate needs the votes of a majority of states, 26 of 50. The District of Columbia has no vote. The Senate chooses the Vice President from the top two, with each senator voting and a majority of the whole Senate needed.
The House last chose a President in 1825, when it picked John Quincy Adams over Andrew Jackson, who had won more electoral and popular votes, and the Senate chose Vice President Richard Mentor Johnson in 1837. A contingent election could follow a 269 to 269 tie, possible under many combinations of states, or a strong third-party showing. The House that decides is the newly elected one, which takes office on January 3, three days before Congress counts the electoral votes on January 6.
If the House has not chosen a President by inauguration day, the Twentieth Amendment provides that the Vice President-elect acts as President, and if neither has been chosen, the Presidential Succession Act points to the Speaker of the House. Critics say one vote per state is undemocratic and could produce a President most voters opposed, and have proposed amendments to abolish the Electoral College or change the procedure. Defenders say it reflects the federal design and has been needed only rarely.
| Status | Active |
| Legal basis | Twelfth Amendment, Twentieth Amendment, 3 U.S.C. 15 |
| Official site | archives.gov |
| Trigger | No candidate wins 270 electoral votes |
| Who picks the President | The House, one vote per state delegation |
| Votes needed | 26 states |
| Who picks the Vice President | The Senate, majority of senators |
| Last time | 1825 for President, 1837 for Vice President |
| Date | Twelfth Amendment ratified June 15, 1804 |