The outcome of Tuesday's election, determining which party will control Congress, is clear in its stakes but uncertain in its timeline. The Associated Press will call races for all 435 House districts and 35 Senate contests.
Control of the House requires a party to secure 218 seats. Currently, Republicans hold 219 seats, just one more than the minimum needed for a majority, with two vacancies. For the Senate, 51 seats are needed for Democrats, or 50 for Republicans, as the Vice President can cast a tiebreaking vote. Republicans presently hold a 53-47 advantage in the Senate.
In past elections, the time to determine control has varied. In the 2022 midterms, the AP called control of the Senate four days after Election Day, while the House call took eight days. During the 2024 presidential cycle, the Senate control was called the day after Election Day, with the House call following eight days later.
Several factors can contribute to delays in vote tabulation. California, the nation's most populous state, often counts thousands of mail-in ballots dropped off on Election Day, with half of its votes in 2022 being counted after Election Day. States like Alaska and Maine, which have key Senate races this year, utilize ranked-choice voting. This system, where votes are redistributed if no candidate achieves over 50% in the first round, can significantly delay results.
The AP does not make projections and will only declare a winner when it is determined that no scenario exists for trailing candidates to close the gap.