How the House of Representatives will choose a president in the event of a tie in the Electoral College

The election has already been filled with eye-popping and historically unusual events. Another potential scenario looms this fall: “contingent elections” for president and vice president, which could occur if no one can secure the 270 electoral votes needed to win the presidency.

That hasn’t happened in the modern era, but the Electoral College map has several possible (though unlikely) paths that could lead to former President Donald Trump and Vice President Kamala Harris ending the race tied at 269 electoral votes.

Some of those scenarios include Republicans winning all the votes in Nebraska, an uphill battle since the state awards votes to the winner in each of its congressional districts and Harris has the edge to win Omaha’s 2nd District. (That’s why Republicans briefly and unsuccessfully tried to change Nebraska’s rules to make it a winner-take-all state.) And it’s much less likely that a third-party candidate would win the electoral votes and prevent someone else from winning a majority, or that faithless voters would refuse to support the candidate with the same end result.

In the event of a tie, Congress will determine the next president.

While this process would be hotly contested and historic, Congress has an established process for selecting a president under this scenario, which would undoubtedly come after a slew of lawsuits in key states aimed at challenging the election results there.

Here’s how it will work.

“Each state, regardless of population, casts one vote for president in a contingent election,” according to the Congressional Research Service. This means that a group of House members from each state will choose one of the three candidates with the most Electoral College votes, and the candidate with the majority of states’ support will win.

The newly elected Congress, which takes office in January, will vote on this scenario. Thus, the results of the congressional elections will be of great importance.

Republicans control a majority of 26 state delegations and Democrats control a majority of 22 state delegations, with two states (Minnesota and North Carolina) tied. Members of Congress will not be required to vote for their party’s candidate, but they will likely face enormous pressure to do so.

Although Washington, D.C. has three electoral votes in the presidential election, it will not have a vote in the House of Representatives in the contingent election because it is not a state.

In a contingent election, the vice president is elected by a full vote of the Senate, with each senator casting a vote for one of the two vice presidential candidates with the most electoral votes.

This article was originally published on NBCNews.com.