With five days until Election Day, the South Carolina Senate race is closer than almost anyone expected in a state Donald Trump carried by nearly 18 points in 2024. Republican Sen. Darline Graham Nordone, also known as Darline Graham, was appointed to the seat after her brother Lindsey Graham’s death in July. She leads Democrat Annie Andrews by about two points in the polling average.
Prediction markets still aren’t convinced Democrats can pull off the upset. Andrews is trading at 27.5 cents on Polymarket, while Graham Nordone sits at 72.5 cents. The PredictionPro model agrees that Graham Nordone is the favorite but gives Andrews a 40.3% chance. That is nearly a 13-point gap between the model and the market.
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South Carolina Senate Race Polls: A Tighter Contest Than the Odds Suggest
The latest polling shows a competitive race:
- RealClearPolling: Graham Nordone ahead by 2.4 points.
- New York Times/Siena (October 19-26): the candidates tied at 48%.
- Targoz: Graham Nordone ahead 47-46.
- East Carolina University (released October 29): Graham Nordone ahead by four points.
The overall picture is a race that looks considerably closer than expected in such a Republican-leaning state. The PredictionPro model combines 15 polls and projects Graham Nordone winning by 2.2 points, almost identical to the broader polling average.
How Lindsey Graham’s Death Reshaped the South Carolina Senate Race
This wasn’t supposed to be a race Democrats had much of a chance in. After Lindsey Graham’s death on July 11, Gov. Henry McMaster appointed his sister, Darline Graham Nordone, to the Senate. She became the first woman to represent South Carolina in the Senate. She went on to defeat Rep. Ralph Norman in the August Republican runoff, winning 52.4%.
Andrews, a Charleston pediatrician who previously ran for Congress in 2022, entered the race with a major fundraising advantage. Through August 5, her campaign had raised $10.8 million, compared with $347,000 for Graham Nordone. Even so, Republicans stayed heavy favorites for much of the campaign, and Cook Political Report still rated the seat Solid Republican in mid-September.
That perception has shifted. Andrews traded around 14 cents at the start of September and was still near 15.5 cents in mid-October. By October 28 she had climbed to 26.5 cents after a roughly $95,000 trading day. The market has nearly doubled her chances in less than two months, and Fox News recently moved its rating of the race to Toss Up.
Larger traders aren’t universally convinced, though. PredictionPro’s tracked sharp-money activity shows one wallet holding about $28,500 against Andrews, compared with just $2,300 in profitable-tier money backing her.
If you’re tracking how the odds have shifted this week, don't forget to visit Prediction Pro and our midterms predictionsfor more political content.
Annie Andrews’ Chances: Why the PredictionPro Model and Polymarket Disagree
The model and the market read the polls almost identically. They differ on how much uncertainty to allow on Election Day.
The model uses a standard error of roughly nine points for the final Senate margin. A candidate trailing by two points still has a meaningful chance of winning, because polling errors, turnout differences and late shifts can easily change the outcome.
Polymarket takes a more conservative view. Its margin-of-victory market prices a Graham Nordone win by zero to five points at 40.5 cents, while the model gives that exact outcome only a 22% chance. Both see a narrow Republican lead. The disagreement is over how reliably that lead holds.
The Case Against Andrews: The Republican Polling Miss
There’s a compelling argument for why traders are less optimistic about Andrews, and it comes from the model itself. PredictionPro’s historical analysis finds an average midterm polling miss of 3.18 points toward Republicans, with errors moving that way in six of the last seven cycles studied.
Adjusting the projected margin by that historical Republican advantage drops Andrews’s win probability from 40.3% to 27.4%, almost exactly where Polymarket is trading. The market may already be pricing in a Republican polling advantage that the baseline forecast doesn’t fully include.
South Carolina has history here. In 2020, polls suggested Lindsey Graham faced a competitive race against Jaime Harrison. Graham won by 10.3 points, outperforming much of the polling. If that repeats, Andrews probably has little path.
But the market is effectively asking traders to pay for a repeat of the historical pattern. If the polls land closer to the actual result this time, Andrews may be significantly undervalued.
Is South Carolina a Tipping-Point Seat for Senate Control?
Probably not. South Carolina isn’t central to the Democrats’ path to a Senate majority. PredictionPro ranks it eighth among potential tipping-point states and gives it just a 6.5% chance of being the decisive seat. That makes this more of an individual race opportunity than a bet on which party controls the chamber.
The Trade: Buying Annie Andrews at 28¢ in the South Carolina Senate Race
This section reflects the author’s opinion, not financial advice.
I lean toward a small position on Annie Andrews at the current 28-cent ask. The baseline model values her at 40.3%, and even a more conservative recalibration puts her at 38.7%. Blending the baseline model equally with Polymarket’s price produces an estimated fair value of 33 cents. That leaves roughly 3.5 percentage points of potential edge after estimated trading costs.
The historical polling-bias adjustment is a legitimate concern. If Republicans outperform the polls by another three points, Andrews’s fair value drops almost exactly to the current market price. I’ll be watching the final polling closely. If Graham Nordone starts consistently leading by five points or more, much of the value disappears.
But with the race polling around R+2, Andrews below 30 cents feels a little too pessimistic. The market is pricing in a familiar Republican polling miss, and I’m willing to take the other side at this price.
My position: Annie Andrews Yes at 28¢, small size.
South Carolina Senate Race FAQ
Who is running for Senate in South Carolina?
Republican Sen. Darline Graham Nordone, Democrat Annie Andrews, Libertarian Kasie Whitener and Mark Hackett are on the November ballot.
When is the South Carolina Senate election?
Election Day is Tuesday, November 3, 2026.
Who is favored in the South Carolina Senate race?
Graham Nordone is the favorite in prediction markets, at about 72.5 cents on Polymarket, and in the PredictionPro model. Polls show her ahead by roughly two points in the average, with some surveys showing a tie.
Why is Darline Graham on the ballot?
Gov. Henry McMaster appointed her to the Senate after her brother, Lindsey Graham, died on July 11. She then won the Republican special primary runoff in August.
