A simple guide to the US midterms
BBCThere are four weeks to go until the US midterm elections, when voters take part in a ballot that could have a major impact on the rest of Donald Trump's presidency.
What are the midterms?
On 3 November, Americans will choose members of Congress, which is made up of two parts - the House of Representatives and the Senate.
Elections take place every two years, and when they happen in the middle of the president's four-year term of office, they are called the midterms.
A key task of Congress is to create and pass federal laws - laws that apply nationwide.
The outcome of the midterms will decide which political party - Trump's Republicans or opposition Democrats - controls Congress and how easy it is for the president to carry out his plans.
The results are also seen as a measure of how happy people in the US are with the president's performance so far.
Who is being elected?
All 435 members of the House - the lower chamber of Congress - will be elected. They serve fixed terms of two years. The House is where proposed laws are introduced and debated.
Meanwhile, 35 of 100 seats in the Senate, the upper chamber, will also be up for grabs. Senators serve six-year terms. Among other jobs, they approve or block proposed laws that have been received from the House.
On the same day, voters across much of the US will also choose state-level politicians. Governor contests in California, Florida, Georgia and Michigan will be among the most closely watched.
What are the key issues?
The US economy is on the minds of many voters struggling with the price of fuel, groceries, housing and healthcare.
Inflation remains above the level targeted by the US Federal Reserve, partly down to the war that the US and Israel started with Iran in February.
Democrats argue Trump's programme of trade tariffs have also pushed up prices for Americans.
Immigration is another key issue. Republicans say Trump has delivered on a major campaign pledge in 2024 by tightening the border and launching a widespread - and often controversial - crackdown on illegal immigration.
Concerns over AI have grown in urgency in recent weeks. Senior politicians from both parties have agreed on the need to regulate it - setting themselves in opposition to Trump, who has rejected the idea of laws to control development of the technology.
What is at stake?
Congress is one of the three branches of government, alongside the presidency and the judiciary. Control of it matters for the shaping of legislation.
Both the House and Senate are currently held by the Republican Party. But its majority is a slender one. They have 218 seats in the House, which is the minimum number needed to control it, plus one independent who votes with them. In the Senate, they have 53 seats and the minimum needed for control is 51.
If opposition Democrats win back control of at least one chamber, they will gain power to bring their own laws to the floor.
Who might win?
Voters have tended to "punish" the party of the president in the past and vote against them.
Recent polling shows a low approval rating for the president. He began his second term as president with an approval rating of just over 50%, according to polling resource website Silver Bulletin, but in early October it was sitting at about 37%. Meanwhile 61% disapproved of him.
But not all seats in each chamber are competitive. Some are a safe bet for Republicans or Democrats.
The BBC's US partner CBS News has identified nine Senate races to watch, in states like Iowa and New Hampshire, and 42 House races, in states like Arizona and Ohio.
The vote is more unpredictable this year because of a battle between the two parties over the way voting districts in the House of Representatives are drawn.
Republicans tried to gain an advantage by creating more favourable electoral maps in certain states and Democrats followed suit.
Getty ImagesWhat does it mean for Trump?
If the Democrats win either the House or the Senate then Trump will find it difficult to get any laws through Congress.
So his domestic plans could be frustrated, although he has found ways to exercise power without his wider party.
Democratic control of either chamber would also mean they could use committees to investigate aspects of the Trump presidency. Corruption allegations, the new White House ballroom and ICE tactics could be subject to scrutiny.
There is also a debate within the Democratic Party about whether to impeach Trump, which means to bring charges in Congress that will form the basis for a political, not criminal, trial.
If the Republican Party stays in control of Congress, Trump will be able to keep going with his plans for the remainder of his time in office.
What does it mean for the 2028 election?
The president's name is not on the ballot during the midterm elections, though Trump has urged Republicans to pretend that it is by voting for him as an endorsement of his actions so far.
Whichever way the results fall, commentators are likely to use them to make arguments about how voters feel about the direction of the country under Trump's leadership.
Trump cannot run to be president a third time. After the midterms, we can expect speculation to start building about who might be his successor as the Republican presidential nominee for 2028 - and who might compete against that person for the Democrats.