When will we know who controls Congress? It could be a while

WASHINGTON (AP) — The stakes in Tuesday's election — which party will control Congress — are crystal clear. But when that will be known is impossible to say.

The Associated Press will be calling races in all 435 House districts and the 35 Senate contests that are up for election this year.

Control of the House depends on which party reaches 218 seats. Currently, 219 members caucus with Republicans, just one more than the minimum needed for a majority when all seats are filled. There are two vacancies now.

The bar for the Senate is 51 seats for Democrats or 50 for Republicans, since Vice President JD Vance can cast a tiebreaking vote for his party. Republicans have a 53-47 edge in the Senate right now.

During the last midterm elections in 2022, the AP called control of the Senate four days after Election Day, while the House call was eight days after.

During the presidential cycle of 2024, there was a bigger gap between the two. Senate control was called the day after Election Day, with the House call coming eight days later.

Some states consistently take days to count all their ballots. California , the nation's most populous, has seen thousands of mail ballots dropped off on Election Day. In 2022 , half the state’s votes were counted after Election Day.

Other states like Alaska and Maine , which have key Senate races this year, use ranked choice voting.

A candidate can win with more than 50% of votes in the first round, but if no one reaches that threshold then the candidate with the fewest first-choice votes is eliminated and their votes are redistributed to the voter's second choice. The process can significantly delay results.

The AP does not make projections and will only declare a winner when it’s determined there is no scenario that would allow the trailing candidates to close the gap.