US Democrats are leading Republicans in almost all seven battleground states expected to determine control of the Senate, according to the polls ahead of midterm elections.

The findings of the polls, conducted by The New York Times and Siena University and published on Monday, gave Democrats an advantage in their bid to regain control of the Senate, while forecast models put their chances of winning a House majority at approximately 95 percent. All 435 House seats and 35 of the Senate's 100 seats are being contested.

Although President Donald Trump is not on the ballot, the elections carry significant implications for the remainder of his presidency.

A Democratic-controlled House could launch investigations, issue subpoenas, and obstruct his legislative agenda.

Republicans, meanwhile, are seeking to retain control of both chambers to advance Trump's priorities.

The elections come amid mounting domestic pressure on Trump over an unpopular war against Iran, which has prompted the Islamic Republic to close the strategic Strait of Hormuz in retaliation for unprovoked American and Washington-backed Israeli attacks.

Closure of the globally vital energy route has unleashed the shockwaves of overarching inflation worldwide, including in the United States, where fuel price hikes have historically damaged incumbent presidents’ popularity.

Concerns over election interference

As more than 54 million Americans have already voted early, according to the University of Florida's Election Lab, concerns have emerged over whether Trump would accept an electoral defeat.

Earlier this year, more than a dozen election officials from both parties expressed fears that he was preparing to undermine the midterm results.

A recent survey found that seven in 10 Americans doubted he would accept the outcome if Republicans lost.

Although the Constitution gives states authority over the administration of congressional elections, Trump's control over federal agencies, including the Department of Justice, FBI, Homeland Security, and the Postal Service, has raised fears of potential interference.

The administration's attempts to influence voting and ballot counting have already encountered judicial obstacles. A federal judge blocked Trump's order restricting mail-ballot delivery, a decision subsequently upheld by the Supreme Court. Courts have also rejected the DOJ's efforts to obtain complete voter registration rolls from 49 states and the District of Columbia to identify alleged “non-citizens” on the rolls. Last month, a judge struck down the policy nationwide.