US midterms will hinge on narrow House margin and seven Senate toss-ups

US midterm elections on 3 November will determine the makeup of Congress for the rest of Donald Trump’s presidency. Republicans currently control both the House of Representatives and the Senate.

The Republican House majority is only one seat wide: the party has 218 representatives, the minimum needed for control, plus an independent who votes with them. All 435 House seats are being contested.

Republicans hold 53 of the Senate’s 100 seats, while Democrats have 45 and two independents vote with them. Thirty-five Senate seats are up for election.

House contest has 21 toss-ups

The Cook Political Report classifies only 21 House districts as toss-ups. Republicans currently hold 15 of them and Democrats hold six.

Democrats would need to win five of those races, in addition to 28 districts rated likely or leaning Democratic, to take control of the chamber.

Historically, the president’s party loses an average of 27 House seats in midterm elections. Since 1934, it has gained seats in only three such elections.

Senate map presents tougher challenge

Seven Senate races are rated toss-ups: six Republican-held seats and one Democratic-held seat. Democrats would need to win four of them while retaining four seats rated likely or leaning Democratic.

They must also defend their seat in Michigan, where polls show a close contest between left-wing outsider Abdul El-Sayed and Republican Mike Rogers, a Trump ally and former FBI agent. Democrats are also targeting Alaska, Iowa and Ohio, states Trump won by double digits in 2024.

In Texas, Democrat James Talarico could become the first Democrat elected to the state’s Senate delegation since 1988 if he defeats Ken Paxton, the state attorney general and a close Trump ally.

Approval and living costs shape vote

Trump’s approval rating, according to Silver Bulletin, fell from just over 50% at the start of his second term to about 37%. One August poll found that 63% disapproved of his handling of the war with Iran.

The cost of living is the leading issue cited by voters. After the war began on 28 February, US petrol prices reached $4 a gallon, compared with Trump’s 24 February statement that prices were below $2.30 in most states. Healthcare and immigration are also important issues.

Republicans hold major cash advantage

At the end of August, the Republican National Committee and allied groups had more than $600m in cash on hand, compared with just under $400m for Democrats. Trump’s MAGA Inc fundraising and spending group held more than $400m separately.

More than $1bn was spent on political advertising in September. Research firm AdImpact said Republicans spent $200m more than Democrats and outspent them in nearly all Senate toss-up races.