What is the 12th Amendment?

The 12th Amendment was ratified on June 15, 1804, after the 1800 presidential election exposed a critical flaw in the original Article II process. Under the original rules, each elector cast two undifferentiated votes for president; the top vote-getter became president and the runner-up became vice president. In 1800, Thomas Jefferson and Aaron Burr each received 73 electoral votes -- a tie -- because Democratic-Republican electors cast both votes for their intended ticket without distinguishing the intended president from the intended VP. The House of Representatives needed 36 ballots over six days to resolve the deadlock, finally electing Jefferson. The 12th Amendment fixed this by requiring electors to cast separate, clearly labeled ballots for president and vice president.

The same-state constraint is the provision with the most direct relevance to 2028 ticket-building. The 12th Amendment requires that one of the two candidates an elector votes for -- president or vice president -- must not be an inhabitant of the same state as the elector. In practice, if a presidential and vice-presidential nominee both reside in the same state, that state's electors face a forced choice: they can vote for the presidential nominee from their state but cannot also cast a valid VP vote for someone from the same state, effectively forfeiting the VP electoral votes from that state. Major-party tickets almost always pick a running mate from a different state to avoid this problem. Dick Cheney changed his legal voter registration from Texas to Wyoming in 2000 before joining George W. Bush's Texas-based ticket, specifically to comply with this rule. For 2028, the same-state constraint affects several potential major-party pairings: Gavin Newsom and Kamala Harris (both California, 54 electoral votes), Pete Buttigieg and Gretchen Whitmer (both Michigan, 15 electoral votes), Marco Rubio and Ron DeSantis (both Florida, 30 electoral votes), and JD Vance and Vivek Ramaswamy (both Ohio, 17 electoral votes).

When no presidential candidate wins an absolute majority of electoral votes -- at least 270 of the current 538 -- the 12th Amendment triggers a contingent election in the House of Representatives. The House chooses the president from the top three electoral-vote recipients, with each state delegation casting a single vote and a majority of all states (currently 26 of 50) required to win. At the same time, the Senate separately chooses the vice president from the top two VP vote-getters, with each senator casting one vote and a simple majority of the full Senate required. A contingent election is historically rare -- it last occurred in 1824, when the House chose John Quincy Adams over Andrew Jackson after neither won an Electoral College majority -- but the closely contested 2028 map means a strong third-party candidate winning a handful of states could theoretically prevent either major-party candidate from reaching 270.

The VP ineligibility clause is the third provision with direct 2028 significance. The 12th Amendment states that 'no person constitutionally ineligible to the office of President shall be eligible to that of Vice-President of the United States.' This clause is why Donald Trump and Barack Obama -- both barred from the presidency by the 22nd Amendment's two-term limit -- are widely regarded as ineligible for the vice presidency as well. The mainstream constitutional interpretation holds that the 22nd Amendment's term limit makes a two-term president 'constitutionally ineligible to the office of President' under the 12th Amendment's language. A minority scholarly view argues that the 22nd Amendment only bars a person from being 'elected' president again and does not technically create 'ineligibility' in the Article II sense, but this narrow reading has not been tested in federal court and is not the dominant legal view.