Donald Trump is hoping to retain Republican majorities in the US House of Representatives and Senate. ( ABC News: Brianna Morris-Grant )
Politics is heating up in the US as the midterm elections draw close.
If you're new to the US political landscape or need a quick refresher, here's a guide to the latest round of elections.
Americans vote on who their next president is every four years.
But they have the chance to decide which political party controls Congress, the US House of Representatives and the Senate, more often.
When a president is being voted in, seats in both chambers are up for election as well.
Midterm elections give voters the chance to change the balance of power at Capitol Hill. ( Reuters: Kylie Cooper )
And then halfway through the president's term, voters head back to the polls to shake Congress up again.
This is known as the midterm elections.
All 435 seats in the House will be up for election, but only one-third of the Senate.
That's because while House members serve two-year terms, senators serve six-year staggered terms.
US President Donald Trump may not be up for election right now, but the outcome of the midterms will shape how much power he has for the rest of his term.
Congress is responsible for making federal laws, controlling the budget and keeping the president in check.
And while the Republican Party (also known as the GOP) currently controls both chambers, it's at risk of losing them both.
Even just one chamber changing over to the Democrats would make Trump's political life much more difficult.
He would find himself having to negotiate with his opponents to get laws and budgets passed, as well as possibly facing increased scrutiny of his actions and business dealings.
Several Democrats have been calling for investigations into Trump and his allies , and if they win back power in congressional committees, they would have the power to follow through.
As part of their investigations, those committees have the power to call on people to testify at hearings and require them to produce documents.
If they uncover evidence of any wrongdoing, they can refer their findings to the Department of Justice for prosecution.
The department is currently run by Trump appointee Todd Blanche.
While Trump will not face voters, his popularity still has a strong influence over the outcome.
The president's party almost always loses House seats in midterm elections and that trend gets steeper when the president is unpopular.
Historical polling data collated by analytics firm Gallup shows presidents with approval ratings below 50 per cent have seen their party lose an average of 37 House seats.
Presidents with approval ratings above 50 per cent have netted smaller losses, with an average of 14 seats.
At the 2018 midterms, Trump had an approval rating of 41 per cent, and the Republicans lost 40 House seats.
This time around, his popularity is sitting at about 37 per cent, according to a polling average by the Silver Bulletin .
They will take place on Tuesday, November 3, 2026, US time.
That works out to run over late Tuesday and into Wednesday afternoon here in Australia.
The ABC will be live-blogging the midterms, and we will have coverage of the biggest stories here .
We can expect to see the results rolling in from the morning of Wednesday, November 4, in Australia.
Officials will start counting votes once the polls close in their state, and results will start being known within a few hours.
Most of the public's votes should be counted on election night in the US .
But because each state has different rules about how ballots are counted and reported, it could take longer for some jurisdictions.
Even if a state counts quickly, we might not see races officially called for days if the margins are close.
With Trump continuing to falsely claim that he won the 2020 presidential election, some commentators believe he will try to dispute the midterms results, leading a bipartisan group of politicians to seek pledges from their colleagues to accept the election's outcome.
