What happens if there’s a tie in the US presidential election?

Kamala Harris and Donald Trump are fighting down to the last vote to gain the upper hand in tomorrow's election. There’s a remote possibility that the US poll could end in a draw, however.

This concerns the machinery of the US Electoral College, the winner-takes-all system that determines which presidential candidate will win the White House.

The Electoral College comprises 538 votes, distributed in varying proportions among the fifty states plus the District of Columbia. A tie between two presidential candidates is therefore theoretically possible.

Harris and Trump could each receive 269 electoral votes, resulting in a complete draw scenario, with both candidates unable to achieve the majority of electoral votes required to become president.

Similar stalemates have occurred twice in US history, in 1800 and 1824.

In the 1800 election, Thomas Jefferson’s Democratic-Republicans defeated the incumbent Federalist President John Adams.

At that time, presidential candidates had a "running mate" from a different state, similar to today’s candidates for vice president. The electors had to cast two votes each: the candidate with the most votes would become president, while the candidate with the second-most votes would become vice president.

However, the Democratic-Republicans did not coordinate well, resulting in their candidate for president (Jefferson) receiving the same number of votes as their candidate for vice president (Aaron Burr).

The election was therefore decided by the House of Representatives using a one-state, one-vote rule after a long deadlock that nearly resulted in a military confrontation, as Sanford Levinson, a professor at the University of Texas Law School, has noted.

For this reason, the 12th Amendmentwas