The Twelfth Amendment is a change to the U.S. Constitution that explains how the Electoral College chooses the president and vice president. It was ratified in 1804, after problems with the original election rules.
Why was an amendment needed?
Under the original Constitution, each elector cast two votes for president. The candidate with the most votes became president, and the runner-up became vice president. This caused trouble in the election of 1800: Thomas Jefferson and his running mate, Aaron Burr, received the same number of electoral votes. The House of Representatives had to choose between them.
What changed?
- Electors cast separate votes. Each elector now casts one vote for president and a separate vote for vice president.
- Candidates are considered for different offices. The president and vice president are elected as distinct positions, rather than the runner-up for president automatically becoming vice president.
- The House resolves a presidential tie. If no presidential candidate wins a majority of electoral votes, the House of Representatives chooses the president from the leading candidates. Each state delegation gets one vote.
- The Senate resolves a vice-presidential tie. If no vice-presidential candidate wins a majority, the Senate chooses the vice president from the leading candidates.
Why does it matter?
The amendment made Electoral College voting clearer and reduced the chance that political rivals would be elected president and vice president because they received the first- and second-highest totals. Its rules for deciding elections without a clear majority still apply today.
In short: The Twelfth Amendment established separate Electoral College votes for president and vice president and set procedures for resolving certain election ties.