Millions of Americans are voting in a midterm election that could reshape the Republican-controlled Congress. Democrats need to gain four Senate seats to take control of the chamber, giving them greater power to block judicial nominations and investigate the Trump administration.
Although 35 Senate seats are being contested and billions of dollars have been spent, seven races are classified as toss-ups by the Cook Political Report. The most closely watched contests include races in Alaska, Maine, Texas, Michigan, Iowa, Kansas and Ohio.
In Alaska, Republican Senator Dan Sullivan is facing former House member Mary Peltola. The contest has been complicated by the appearance of a second candidate named Dan Sullivan on the ballot. The incumbent accuses Peltola's campaign of helping create confusion, an allegation she denies. The issue is under state investigation, while a related Justice Department lawsuit was rejected by a judge.
Peltola, the first Alaska Native elected to Congress, has campaigned on the message of “fish, family, freedom” and criticised Sullivan's record as the state's natural resources commissioner. Sullivan, a former Alaska attorney general and long-serving Marine reservist, is seeking another term. Alaska's ranked-choice voting system and its historically difficult-to-poll electorate add uncertainty to the result.
Maine is also hosting a closely watched contest between Republican Senator Susan Collins and Democrat Troy Jackson. Collins, who is seeking a sixth term, is one of the few Republicans who voted to convict Trump during his 2021 impeachment trial. She has often outperformed her party in the Democratic-leaning state by presenting herself as a centrist.
Jackson, a former president of the Maine state senate and a logger, is attempting to appeal to blue-collar voters. Both candidates oppose Trump's tariffs on Canada, while Jackson also supports abolishing Immigration and Customs Enforcement. Collins has been helped by controversy surrounding the Democratic nomination, which ultimately went to Jackson.
Texas Democrat James Talarico is trying to end his party's decades-long losing streak in statewide elections by defeating Republican Ken Paxton. The race has become the most expensive Senate contest ever, with Paxton receiving more than $170m in support from tech entrepreneur Elon Musk, according to the campaign account described in the source material.
Paxton, the state's former chief legal officer, was impeached by the Republican-controlled Texas House in 2023 over allegations including corruption, bribery and abuse of power. He denied the accusations and was acquitted by the state Senate, calling the impeachment politically motivated. Talarico, a state representative and former teacher, has made the case central to his campaign, while Paxton has attacked his Democratic opponent's positions on immigration, energy, law enforcement and transgender rights.
In Michigan, Democrat Abdul El-Sayed is seeking to retain a key seat against Republican Mike Rogers, a former FBI agent and congressman. El-Sayed, a doctor and public health official, supports government-run health insurance and abolishing ICE. He would become the first Muslim person elected to the Senate if successful.
Rogers has emphasised his military and intelligence background while maintaining Trump's support, despite disagreements with the president over tariffs and other issues. Trump and Rogers have tried to associate El-Sayed with the Muslim Brotherhood, which El-Sayed has denounced. Trump's references to the September 11 attacks and his description of El-Sayed as a “jihadist” without citing evidence have drawn accusations of Islamophobia.
Iowa's contest pits Republican former television news host Ashley Hinson against Democrat Josh Turek, a wheelchair basketball player who won gold medals at two Paralympic Games. The race has focused on farming, tariffs and Trump's policies, with the candidates taking different positions on the economic impact of the president's trade measures.
Hinson has maintained some distance from Trump, including by urging an end to the war with Iran and opposing the easing of beef tariffs, while defending his broader tariff policy. Turek argues that tariffs have harmed the state's farmers and raised fuel and fertiliser costs. The candidates have also clashed over taxes, Social Security and immigration. Iowa has not elected a Democrat to federal office in nearly 20 years.
Kansas could deliver one of the biggest historical surprises. A Democratic victory would be the state's first Senate win for the party since 1932. Republican Senator Roger Marshall is facing Methodist pastor Adam Hamilton, who has campaigned on reducing costs, protecting healthcare access and bridging the partisan divide.
Marshall has presented himself as aligned with Trump and supportive of farmers, while portraying Hamilton as too progressive for Kansas. The senator has also faced scrutiny over reports that he sued patients who could not pay medical bills, a claim he described as a politically motivated attack. Both candidates are fifth-generation Kansans, but their contrasting messages have made the race a test of Republican strength in the state.
Ohio was not widely considered competitive a year ago, after Trump won the state comfortably in 2024. Republican Senator Jon Husted, appointed in 2025 to the seat vacated by Vice-President JD Vance, is now running to complete the remainder of Vance's term. He is being challenged by Democrat Sherrod Brown, who represented Ohio in the Senate for many years before losing his seat.
Husted has highlighted his business background and promises to support jobs and growth. Brown, known for his focus on workers and economic populism, is relying on high name recognition built over three decades in Ohio politics. The campaign has become a referendum on Trump's economic agenda, particularly the trade disputes affecting the manufacturing and automotive industries that are central to the state's economy.
The outcome of these contests could determine control of the Senate and shape the political limits facing Trump during the final two years of his presidency.
Sources: BBC News World.