Americans head to the polls for Tuesday's midterm elections

Voters in the United States will head to the polls on Tuesday to cast ballots in the midterm elections that will decide whether Republicans or Democrats control Congress.

The result will also affect how easily Donald Trump can pursue his plans for the rest of his term.

Republicans currently hold the House with 218 seats, the minimum required for control. In the Senate, they hold 53 of the 100 seats, meaning Democrats need 51 seats to take control because the vice president, who is currently a Republican, breaks a 50-50 tie.

All 435 House seats are up for election, along with 35 Senate seats, with House members serving two-year terms and senators serving six-year terms.

Why do midterms exist?

Congress writes and passes the laws that apply across the country, and midterm elections happen halfway through a president's four-year term to provide a verdict on the president's performance so far.

Voters have tended to turn against the president's party in past midterms.

Many people are struggling with the cost of fuel, groceries, housing and healthcare. Inflation remains above the US Federal Reserve's target, partly because of the war that the US and Israel started with Iran in February.

Democrats say Trump's trade tariffs have pushed prices up further.

Republicans point to immigration, saying Trump kept a 2024 campaign pledge by tightening the border and launching a widespread crackdown on illegal immigration. 

Artificial intelligence has also moved up the agenda in recent weeks. Senior figures in both parties say it needs regulation, but Trump has rejected the idea of laws to control it.

Trump's approval rating adds to the uncertainty, as it was just over 50% when his second term began, according to the polling website Silver Bulletin, but stood at about 37% in early October, with 61% disapproving.

What changes if Democrats win

Winning either chamber would make it hard for Trump to pass laws, although he has found ways to use power without his wider party. It would also give Democrats the ability to bring their own bills to the floor.

If Republicans keep Congress, Trump can carry on with his plans until his term ends.

The look ahead to 2028

Trump is not on the ballot, but he has urged Republicans to vote as if he were, as a show of support for his actions so far.

He cannot run for a third term, so once the votes are counted, Americans will begin talking about who might become the Republican nominee in 2028, and who might face that person for the Democrats.