On this date in 1801, the fourth presidential election in the United States' history was finally decided. Presidential electors (which at that time could vote for two candidates) had cast 73 ballots each for Thomas Jefferson and Aaron Burr. This caused the election to be decided in the House of Representatives, which cast 36 ballots in 6 days. For the first 35 ballots, Jefferson won 8 states - one short of the required 9. Finally, on the 36th ballot, representatives from Maryland and Vermont changed their votes, giving Jefferson 10 states and the win. The Constitution was amended in 1804 to change these rules so electors would distinctly select and president and vice-president with their votes.