A Handful of Seats Will Decide Control of Congress: The US Midterm Map Explained

A turning point in Donald Trump's second term is approaching in the United States. On 3 November, voters will decide whether Congress remains in the hands of the president's Republican allies or whether Democrats return to the majority. Maps and analysis published ahead of the midterm elections suggest the fight will be decided by a remarkably small number of seats.

Many indicators of voter sentiment suggest Democrats are favoured to take back the House of Representatives, and potentially the Senate as well. Winning either chamber would be a significant victory, giving the party the power to block Trump's legislative agenda and to investigate his administration more aggressively.

Republicans currently hold 53 of the Senate's 100 seats, while Democrats and their allies hold the remaining 47. Senators serve six-year terms, so a third of the seats face voters in each two-year cycle; 35 seats are on the ballot this November. To win a majority, Democrats must capture at least four seats currently held by Republicans.

In practice, however, the battle for the Senate is being fought across a very small map. The Cook Political Report, a prominent US election forecaster, currently lists seven seats as tossups: Alaska, Iowa, Kansas, Maine, Michigan, Ohio and Texas. New Hampshire is rated as leaning towards the Democrats, while South Carolina is leaning towards the Republicans.

At the start of 2026, Republicans appeared well positioned in the Senate battle. But as Trump's approval ratings fell over the course of the year amid discontent with the Iran war and rising gas prices, Cook and other major forecasters shifted several races in the Democrats' direction. Georgia is a key example, now rated as a likely Democratic win.

Texas offers another sign of Democratic momentum. The longstanding Republican stronghold is considered in play this year, and recent polls show the Democratic candidate ahead by a razor-thin margin. A Texas victory would be historic for Democrats: no Democrat has won a Senate race in the state since 1988, and Texans last voted for a Democratic president in the era of Jimmy Carter in the 1970s. In 2024, Trump won the state with 56 percent of the vote to Kamala Harris's 42 percent.

Running for the Texas seat is state representative James Talarico, who has focused on wealth inequality and called for billionaires to pay higher taxes; 'It's time to start flipping tables' is his campaign slogan. The Republican nominee, state attorney general Ken Paxton, has highlighted his close relationship with Trump. The president endorsed Paxton in a video filmed in the Oval Office, praising his work defending the southern border, to which Paxton replied: 'Thank you very much, President Trump. We won't let you down.'

Michigan is another neck-and-neck contest. In a seat left open by a retiring Democrat, Republican Mike Rogers faces progressive Democrat Abdul El-Sayed, who has been endorsed by figures such as Harris and Bernie Sanders and is currently polling slightly ahead. Michigan is a swing state at presidential level, but Democrats have a long history of Senate victories there, and no Republican has won a seat since 1994. El-Sayed, a former public health official, is campaigning on Medicare for All — expanding the programme for elderly and disabled people to every American. Polling suggests close to half of Michigan voters support the idea, though a sizeable number remain opposed.

Iowa may also prove a big test of Democratic fortunes. The state twice backed Barack Obama before growing very Republican, and it has not elected a Democratic senator since 2008. This year, polls indicate Democrats may have a chance: Republican Ashley Hinson is neck-and-neck with her Democratic rival Josh Turek. Hinson has tried to keep the party's agricultural base on side by championing the year-round sale of gasoline with a higher biofuel content, which could lower prices at the pump and boost farmers financially. Turek, a two-time Paralympic gold medallist in wheelchair basketball, recently released a campaign video in which he shoots hoops with Barack Obama, the last Democratic president to win Iowa.

The House, too, is up for grabs, and it is also currently controlled by Republicans. Every seat is contested, as members serve only two-year terms. Overshadowing the House elections is an unprecedented level of politically motivated redistricting: after Trump set off a redistricting war last year, nine states have redrawn congressional boundaries, some to benefit Democrats and others Republicans, with analysis suggesting Republicans will gain more seats overall. The new maps have faced legal challenges — a Democratic gerrymander in Virginia was struck down by the state supreme court, while the US Supreme Court rejected a Republican attempt in Missouri.

The redistricting has not dashed Democratic hopes of taking the House. The Cook Report rates more than 40 races as competitive, and winning around half of them would hand Democrats a majority. In New York City's exurbs, Republican Mike Lawler hopes to win a third term by turning voters against democratic socialist mayor Zohran Mamdani. In northwestern Ohio, Marcy Kaptur, who has represented her district since 1983 and is the longest-serving woman in Congress, faces a tougher re-election after redrawn boundaries increased her district's Republican lean. In a California district, the One Big Beautiful Bill is a major issue: Republican incumbent David Valadao voted for the Trump-backed measure, which extends tax cuts for wealthy people and corporations while slashing Medicaid, and his constituents have some of the highest Medicaid enrolment rates in the country.

Whichever party wins the House may achieve only a single-digit majority, as Republicans have had for the past four years — though a 'blue wave' of Democratic wins even in districts Trump carried by wide margins in 2024 remains possible. History favours the party out of power in midterms: all recent presidents have lost control of a chamber in midterm elections, including Trump himself in 2018.

Polling shows a nationwide shift towards the Democrats in the run-up to the vote, even in states Republicans have dominated for decades, with generic ballot surveys giving Democrats an edge ranging from the high single digits to the low double digits. The events of this year — notably the Iran war and its impact on inflation, particularly gasoline and diesel prices — have changed the race, and Democratic candidates across the key contests are campaigning on affordability, with surveys rating the economy as by far the most important issue for voters. Only the 3 November vote will show whether that shift is enough to redraw the balance of power in Congress.