Americans vote on November 3 in midterm elections that will decide whether President Donald Trump's Republicans retain control of Congress or spend the final two years of his term confronting Democratic majorities.
High living costs, the war with Iran and Trump's poor approval ratings have helped Democrats expand the electoral map, with unusually tight contests even in Republican strongholds.
But polling errors, redrawn districts and record campaign spending make the outcome uncertain.
- The arithmetic -
Republicans hold a 53-47 Senate majority. Democrats need a net gain of four seats to take the upper chamber of Congress. A 50-50 tie would leave Republicans in charge through Vice President JD Vance's tie-breaking vote.
All 435 House seats are contested. With 218 Republicans, 214 Democrats, one Republican-aligned independent and two vacancies, Democrats need at least 218 seats in the new lower chamber for a majority.
Unlike the Senate, the House battle is spread across dozens of districts rather than a handful of statewide contests.
- Senate: eight battlegrounds -
North Carolina: Former Democratic governor Roy Cooper faces Republican operative Michael Whatley in a bid to flip the seat vacated by the retirement of Thom Tillis, a vocal Republican Trump critic. Strong polling for Cooper has prompted both parties to shift some spending elsewhere, but the contest remains key for Democrats.
Texas: Democrat James Talarico, a Christian progressive, faces Trump-backed Attorney General Ken Paxton, whose controversies have helped turn a longtime Republican stronghold into a closely watched contest. Paxton retains a loyal conservative following and enormous outside financial support.
Ohio: Former Democratic senator Sherrod Brown seeks a comeback against Republican Jon Husted, who was appointed to replace Vance. Among the country's most expensive races, it's also a test of whether economic discontent can shift a state that has moved sharply rightward.
Maine: Republican Susan Collins faces former state Senate leader Troy Jackson. She has repeatedly survived difficult elections in a state that votes Democratic for president.
Alaska: Former Democratic congresswoman Mary Peltola challenges Republican Daniel Sullivan. Her strong standing among voters has made another Trump-voting state unexpectedly competitive.
Iowa: Republican congresswoman Ashley Hinson and Democrat Josh Turek compete for retiring Republican senator Joni Ernst's seat, while soaring agricultural and energy costs are prominent issues.
Kansas: Democratic pastor Adam Hamilton is challenging Republican Roger Marshall in a state that has not elected a Democratic senator since 1932. Tight polling has prompted Trump to campaign for Marshall.
Michigan: An important Republican pickup opportunity pits former congressman Mike Rogers against progressive Democrat Abdul El-Sayed, to fill retiring Democratic senator Gary Peters' seat.
- The House: watch the suburbs -
New York's 17th district: Republican Mike Lawler faces Democrat Cait Conley in a Hudson Valley seat won by Kamala Harris in the 2024 presidential election.
Nebraska's 2nd: Republican Don Bacon's retirement leaves a competitive Omaha-area seat contested by Republican Brinker Harding and Democrat Denise Powell.
Pennsylvania: Republican incumbents Ryan Mackenzie, Rob Bresnahan and Scott Perry face closely watched Democratic challenges. Nearby New Jersey's 7th district, where Rebecca Bennett challenges Republican Tom Kean Jr., is also in play.
Virginia's 2nd: Democrat Elaine Luria is seeking to reclaim the coastal seat she lost to Republican Jennifer Kiggans in 2022.
Iowa: Three Republican-held districts in the east and center of the state could provide an early indication of whether Democrats are making broad gains.
- Governors: another test of Republican strength -
Governors do not determine control of Congress, but 36 states are electing them, with several unusually competitive contests.
In Texas, Democrat Gina Hinojosa is challenging three-term Republican incumbent Greg Abbott, while Iowa pits Democrat Rob Sand against Republican Zach Lahn.
In Ohio, Democrat Amy Acton faces Republican Vivek Ramaswamy, while Nevada's Republican governor Joe Lombardo is defending his office against Democratic attorney general Aaron Ford.
- Under the radar: signs of a wave? -
For an indication of the scale of any Democratic advance, watch two Republican-held Virginia house districts: the 1st, where Shannon Taylor challenges Robert Wittman, and the 5th, where former congressman Tom Perriello wants to unseat John McGuire.
A Democratic gain in Kentucky's Republican-leaning 6th district, or unexpected defeats for Republicans in Florida's 13th and Wisconsin's 1st, would likewise signal a particularly broad electoral swing.
Conversely, Democrats face dangers of their own in redrawn districts, including Alabama's 2nd, where Shomari Figures is defending his seat, and Texas's 34th, where Vicente Gonzalez faces Republican Eric Flores.
AFP