What happens if neither Harris nor Trump win 270 electoral votes?

Former United States president Donald Trump and Vice President Kamala Harris were caught in a tight competition on Tuesday as Americans voted to decide who ends up in the White House.

Based on the US election process, a presidential candidate needs to win at least 270 electoral votes to become the president of the country. However, there is a possibility that no single candidate secures the necessary Electoral College votes to win the presidency.

This situation, which is known as a "contingent election," may occur through a rare 269-269 tir or if a third-party candidate garners enough electoral votes to prevent a clear victory for the Democratic and Republican candidates.

Here's how the US Constitution describes the plan for when this happens. 

In case of an Electoral College tie, the election would be decided by newly-elected members of the House of Representatives according to the 12th amendment.

For the House vote, each state's House delegation receives one combined vote. 

The candidate who receives a majority of state votes, which is 26, becomes the president.

Meanwhile, the vice president is decided by the Senate with a simple majority vote. Each senator gets one vote.

If the House vote ends in a tie, representatives are instructed to keep at it until one state flips. If there is no decision by Inauguration Day, the vice president-elect becomes acting president until the House breaks the tie.

A contingent election is a rare occurrence in US history as the last time it happened was hundreds of years ago.

It happened 224 years ago, in 1800, when Thomas Jefferson and Aaron Burr — both from the Democratic-Republican Party — tied with 73 electoral votes each, leading the House to select Jefferson as the winner.

Then, it happened again in 1824 when John Quincy Adams defeated Andrew Jackson — both representing the Democratic-Republican Party. 

Jackson had more electoral and popular votes than Adams, but neither had a majority because others also received electoral votes. The House gave the election to Adams.