GOP Sends $5M to Defend South Carolina as Prediction Markets Still Heavily Favor Graham

Republicans are sending reinforcements to South Carolina, a state they should not have to rescue.

The Senate Leadership Fund, the Super PAC aligned with Republican Majority Leader John Thune, plans to spend $5 million supporting Sen. Darline Graham as polls show Democrat Annie Andrews within a point. A Republican source described the investment as an “insurance policy” to Axios, with much of the money intended for television advertising reminding voters that Andrews is a Democrat.

Prediction markets are considerably less alarmed. Graham is trading at 86% on Kalshi, where more than $2.3 million has poured into the contract, and 84% on Polymarket, with nearly $700,000 in volume.

That puts South Carolina alongside Wisconsin’s governor’s race as another sharp disagreement between close polling and confident market prices. Surveys suggest Republicans have a real problem. Traders still expect the state’s Republican lean to carry Graham through.

Two polls, one-point margins

Recent polling gives Andrews a credible reason to believe the race is competitive.

A Trafalgar Group survey of 1,087 likely voters conducted Sept. 23-25 found Graham ahead 43.4% to 42.3%. The 1.1-point gap sits within its 2.9-point margin of error, with 8.5% undecided and 5.9% supporting another candidate.

An InsiderAdvantage poll of 1,200 likely voters similarly put Graham at 46% and Andrews at 45%, within its 2.83-point margin of error. An earlier September Rasmussen survey gave Graham a wider 5-point lead, so the polling is not uniformly a dead heat, but it also doesn't show an uncomplicated Republican hold.

Those findings are striking in a state President Donald Trump carried by roughly 17 points in 2024. South Carolina is not ordinarily part of Democrats’ realistic Senate pickup map.

A new incumbent, a funded challenger

Graham has held the seat only since July, when Gov. Henry McMaster appointed her following the death of her brother, Sen. Lindsey Graham. She entered the general election with the advantages of incumbency and Trump’s backing, but without her brother’s decades-long political record.

Andrews, a pediatrician and former congressional candidate, has built a substantial financial advantage. NBC News reported that her campaign spent $6.1 million on advertising since the beginning of September, compared with $687,000 from outside Republican groups over that period.

That disparity helps explain why national Republicans are stepping in. Graham has struggled to raise money while competing for attention with Republican candidates in more established battlegrounds. Local reporting also described her public campaign presence as limited.

The new $5 million commitment is therefore meaningful, without necessarily signaling panic. Republicans can believe Graham is likely to win and still decide that leaving the race underfunded is an unnecessary risk.

Traders still favor the GOP

The prediction markets view is much more decisive than the polling.

Polling support and win probability are different measures. A survey estimates whom voters currently support. A market price reflects traders’ assessment of who will ultimately win.

Still, an 86% Republican probability alongside repeated one-point polling leads is a substantial gap. The markets appear to be assigning considerable weight to South Carolina’s partisan fundamentals, even as the polls suggest those fundamentals are being tested.

A useful distinction also exists between a race becoming competitive and a Democrat becoming favored. Andrews can force Republicans to spend, narrow the margin, and create a plausible upset scenario without yet becoming the most likely winner. That is effectively where traders have placed this contest.

Another Senate-control opening

Democrats need a net gain of four seats to take the Senate. Their most visible opportunities have included North Carolina, Maine, Ohio and Alaska, with Texas and other Republican-held states expanding the potential map.

South Carolina would be an additional route. Democrats did not initially expect to need or win it. Recent New York Times/Siena polling across several reliably Republican states has helped fuel Democratic hopes that the battleground is broadening.

For Republicans, the problem is partly the seat and partly resource allocation. Money spent protecting Graham is money unavailable to defend other Republican seats or target vulnerable Democrats. The $5 million commitment shows that national Republicans consider the risk worth addressing, even if they still expect to prevail.

An Oct. 11 debate in Columbia will give Graham, Andrews and Libertarian candidate Kasie Whitener another opportunity to reach voters before the 2026 midterm elections. With undecided voters and minor-party support potentially larger than the polling margin, the closing weeks could matter.

South Carolina may still finish where prediction markets expect: in Republican hands. But the GOP is now spending to make sure, and Andrews has made a presumed stronghold part of the Senate conversation.