Countdown to Midterms: Two More Senate Seats in Play

Republicans are already on the defensive heading into November, with coin-flip odds of holding Republican Senate seats in states that President Trump won by 10 or more points in 2024. Some recent polls indicate that two more states could be added to the list of seats Republicans will have to defend in the midterms.

South Carolina

The latest InsiderAdvantage poll found Darline Graham leading Democratic opponent Dr. Annie Andrews by just 1.9 points, 45.1%-43.2%. That is a narrow margin for South Carolina, where Trump won by 17.9 points in 2024, and Lindsey Graham won his last reelection campaign in 2020 by 10.3 points.

Darline Graham was appointed to replace her brother, the late Sen. Lindsey Graham, after his death in July and later narrowly won the South Carolina Senate special primary runoff on Aug. 25. Graham received 52.4% of the vote to Rep. Ralph Norman’s 47.6%, securing the Republican nomination for the November election.

The cross tabs of the InsiderAdvantage poll suggest independents are a major reason for the close margin. Self-identified Republicans and Democrats backed their respective candidates, but independents favored Andrews over Graham, 42.1% to 28.6%. Another 24.8% of independents remained undecided, leaving a sizable bloc still up for grabs. Graham has agreed to debate Andrews on Oct. 11.

Kansas

Kansas Sen. Roger Marshall also faced a somewhat concerning new poll over the weekend. The co/efficient poll, conducted Sept. 8-10 among 915 likely voters, found Marshall leading Democratic opponent Adam Hamilton, the senior pastor of one of the largest United Methodist churches in the U.S., by just 5 points, an unusually narrow margin for a Kansas Senate race.

Hamilton’s centrist positioning has helped keep him competitive with Marshall, even in a state Trump won by 16 points in 2024. Before running, Hamilton considered an independent bid but ultimately decided to run as a Democrat to avoid splitting the anti-Marshall vote, the Associated Press reported. During the Democratic primary, he drew criticism from Democrats such as state Sen. Patrick Schmidt, whose spokesman said Hamilton was not a Democrat “when it counted most,” noting that he was a registered Republican during the August 2020 primary.

Hamilton still faces long odds in a state where no Democrat has won a U.S. Senate seat since 1932. Betting markets give him a 22% chance of winning, putting him well behind Marshall but still ahead of Republicans’ odds in the 2024 swing states of Georgia and North Carolina.

South Carolina and Kansas add to the four other Republican-leaning states the GOP will need to defend in November: Texas, Ohio, Alaska, and Iowa. This broader battlefield gives Democrats more chances to gain seats while also requiring Republicans to divide their time, money, and attention across more races. In betting markets, Democrats have taken a slight lead, with a 53% chance of winning control of the Senate in 2026 despite a map that is favorable for Republicans.