The 12th Amendment, ratified in 1804, cleared up a mess created by the Founders in the matter of how presidential elections were resolved by the Electoral College. The Constitution’s original provision for electing a president and vice president didn’t survive the bitter 1800 election between Thomas Jefferson and John Adams. The original Article II, Section 1, of the Constitution required electors in states to cast two separate ballots—one for president and one for vice president. It was up to the political parties to coordinate among their electors to make sure their vice-presidential candidates had at least one fewer electoral vote than presidential candidates. However, there was a “communication breakdown” within Jefferson’s party, when someone forgot to not vote for Jefferson’s running mate, Aaron Burr. After the electoral votes were counted, Jefferson and Burr each had 73 votes, and tied as the winner. (Jefferson had actually received 61 percent of the popular vote.) Worse yet, Article II sent the tie election to the House, which was controlled by Adams’ Federalist Party. (starting to sound familiar?) The contingent runoff election between Jefferson and Burr was a true constitutional crisis. Jefferson ultimately won the House election on the 36th ballot after a week of voting. (more echos to today...) Alexander Hamilton, Jefferson’s long-time enemy, supported Jefferson instead of his old rival from New York, Burr. (Hamilton considered Jefferson as the least dangerous of the two options.) Another factor that concerned Congress after the 1800 election was the outcome of the 1796 election, when members of opposing parties (Adams and Jefferson) were elected president and vice president. After this crisis, the 12th Amendment quickly followed. It was written, approved in Congress and ratified within three years, so that it was in effect for the 1804 election. (The next amendment to the Constitution wouldn’t be ratified until December 1865.) see https://constitutioncenter.org/blog/the-day-that-the-12th-amendment-worked
