American voters have the chance to make or break Donald Trump’s presidency on Tuesday, with midterm elections taking place across the United States.

They will decide the makeup of the US Congress, with hundreds of seats being contested across the House of Representatives and the Senate. This will determine how easily Trump can pass his political agenda and how much scrutiny his administration faces.

Elections will be also be held for state assemblies and governors, city mayors, councillors, officials and even judges.

But the vote is often viewed as a de facto referendum on the sitting president – and it isn’t looking good for Trump.

The midterm elections take place every two years, in the middle of a president’s four-year term of office. This year, all 435 members of the House will be elected for two-year terms. In the Senate, 35 of 100 seats are up for election, for six-year terms.

In the House, Republicans currently hold 218 seats to the Democrats’ 214. There is one independent member and two vacancies. In the Senate, the Republicans have 53 seats compared with the Democrats’ 45 – although two independents caucus with the Democrats.

Current polling suggests the are likely to win the House of Representatives, and have a good chance of winning the Senate, with some suggestions these could be the worst midterm elections for any president, ever.

Data-modelling site Race to the White House gives the Democrats a 94 per cent chance of taking the House and a 76 per cent chance of winning the Senate. An NBC News survey conducted in the final days of October found Democrats generally ahead by 52 per cent to 45 per cent across the country.

Another poll found Democrats beating Republicans in nearly all of the seven battleground states that will determine who controls the Senate.

This is largely down to the soaring cost of living, which has been exacerbated by Trump’s , and consistently polls as the top issue for voters.

Dr Jonny Hall, a US foreign policy lecturer at the London School of Economics, said the midterms were “traditionally seen as a kind of referendum for the first half of a presidential administration”, especially if one party has controlled the presidency, the Senate and the House of Representatives – as has been the case for the last two years.

“The general pattern is very clear; incumbent governments tend to lose congressional seats in these elections,” Hall said. “As such, it is normally harder for presidential administrations to govern in the last two years of their term – congressional oversight may grow, and Congress, vitally, has the power of the purse which it can use to extract concessions.”  

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