Control of the Senate will be settled in a handful of states on 3 November. Republicans hold 53 seats, so Democrats need a net gain of four. That makes every poll from the races below a potential mover in the midterm odds. Several are open seats, while others pit long-serving senators against well-known challengers.

All polling margins quoted are Decision Desk HQ averages from late September.

Texas: James Talarico v Ken Paxton

Ken Paxton, the state's attorney general, beat four-term senator John Cornyn in a runoff on 26 May with 63.8% of the vote, helped by a late endorsement from Donald Trump. Cornyn became the first Texas senator to lose renomination since 1970.

James Talarico, a state representative, won the Democratic nomination with 52.4% of the vote against congresswoman Jasmine Crockett. He leads by 2.4 points. Democrats have not won a Senate race in Texas since 1988, and Trump carried the state by nearly 14 points in 2024.

North Carolina: Roy Cooper v Michael Whatley

Thom Tillis dropped his re-election bid after voting against Trump's One Big Beautiful Bill Act, leaving the seat open. Michael Whatley, the former Republican National Committee chair, won the nomination with 64.6% of the vote after Trump endorsed him.

Democrats turned to Roy Cooper, who served two terms as governor from 2017 to 2025 and took 92% in his primary. Cooper leads by 8.6 points, the widest margin of any race here. Democrats have not won a Senate race in North Carolina since 2008.

Ohio: Sherrod Brown v Jon Husted

This is a special election for the seat JD Vance left to become vice president. Governor Mike DeWine appointed his lieutenant governor, Jon Husted, who ran unopposed for the Republican nomination. The winner serves the rest of the term and faces voters again in 2028.

Sherrod Brown represented Ohio for three terms before losing to Bernie Moreno by just over 3.5 points in 2024. He now leads Husted by 4.5 points in a state Trump won by 11 points.

Maine: Susan Collins v Troy Jackson

Susan Collins is seeking a sixth term and is the only Republican senator up for re-election in a state Kamala Harris won. She has beaten the polls before. Almost every survey had her losing in 2020, and she won by nine points.

Her opponent arrived late. Graham Platner won the Democratic primary on 9 June but withdrew on 10 July following sexual assault accusations and other controversies. A party convention chose Troy Jackson, the former Maine Senate president, to replace him on 25 July.

Jackson leads by 0.1 points, the tightest race on the map. Maine counts by ranked-choice voting, so the result may not be known on election night.

Alaska: Mary Peltola v Dan Sullivan

Mary Peltola, a former congresswoman, topped the nonpartisan primary on 18 August with 49.5% of the vote to Dan Sullivan's 41.4%. Sullivan is seeking a third term, and Democrats have not won a Senate race in Alaska since 2008.

Peltola leads by 1.2 points. Alaska also uses ranked-choice voting, so a slow count is likely here too.

Michigan: the seat Democrats must defend

Gains elsewhere count for little if Democrats lose ground at home. Gary Peters is retiring, and Michigan is the only open Democratic seat in a state Trump won in 2024.

Abdul El-Sayed, the former Wayne County health director, won the Democratic primary on 4 August with 48.5% of the vote. He faces Mike Rogers, the Republican nominee in 2024, and leads by 3.9 points.

What it means for the Senate

Democrats lead in all five Republican-held seats above. Flipping four of them while holding Michigan and their other seats would give them 51 seats and the majority.

Most of those leads are inside the range of a normal polling miss, and Maine and Alaska are close to level. Those races will drive much of the movement in the political odds between now and polling day.