Millions of Americans are participating in midterm elections that will significantly influence the remainder of Donald Trump's presidency, with the outcomes dictating which party controls Congress. The process of determining winners, particularly for the House of Representatives and the Senate, may extend beyond election night.

These elections are crucial as they decide the balance of power in Washington. Control of Congress means the president's party can more easily advance its legislative agenda, while the opposition party can exert greater influence through oversight and by blocking key appointments and legislation.

Initial results will begin to be reported after polls close at 18:00 EST (23:00 GMT). However, early returns are likely to come from districts considered safe for either Republicans or Democrats, offering limited insight into the broader national picture. Analysts will closely monitor competitive races, such as those in Ohio and Maine, for early indicators of voter sentiment.

Major US media organizations utilize projection models to determine race outcomes before all votes are counted, declaring a winner when a lead is deemed insurmountable. Nevertheless, in closely contested states, these projections can be delayed, potentially prolonging the wait for definitive results.

The final determination of which party controls Congress hinges on the competitiveness of individual races and the number of contests that remain too close to call. The complexity of vote counting and tabulation processes, especially in states with tight margins, can contribute to extended result timelines.

In the 2022 midterm elections, the race for control of Congress remained highly competitive for several days after election day. While Republicans were favored to secure a House majority, the Senate outcome was uncertain for an extended period. CBS News did not project a Republican House majority until November 17, and a pivotal Senate race in Nevada required four days of counting, ultimately resulting in a narrow Democratic victory that secured them 50 seats.

The current election involves all 435 seats in the House of Representatives. In the Senate, 35 of the 100 seats are being contested, as senators serve six-year terms. The composition of the House requires a majority of 218 seats for either party. For the Senate, 51 seats are needed for an outright majority, though a 50-50 split would grant control to the party whose vice-president holds the tie-breaking vote.

As vote counting progresses, voters and officials will be closely watching the developing totals, with the final picture of congressional control potentially taking days or even weeks to fully materialize, depending on the closeness of the races.