Sen. Darline Graham Nordone has the appointment, President Donald Trump’s endorsement and the strongest prediction market price in South Carolina’s special Senate race.
What she still lacks is the Republican nomination.
The interim senator, appointed to fill the seat left vacant by her late brother, Sen. Lindsey Graham, failed to win a majority in the crowded August 11 GOP primary, despite carrying strong favorite odds on prediction markets.
That forces her into an August 25 runoff against Rep. Ralph Norman, turning what was supposed to be a relatively straightforward succession story into a real test of the Trump endorsement and the Graham family brand.
The primary did not settle it
Graham Nordone entered the primary as the clearest market favorite. She was trading in the low 60s on Kalshi and Polymarket while Norman and Rep. Russell Fry split the rest of the serious market interest. But the 10-candidate field prevented anyone from reaching the 50% threshold needed to avoid a runoff, and Norman emerged as the candidate with the clearest path to consolidate anti-Graham votes.
That was always the risk. The early polling showed no dominant candidate, with one Emerson College survey putting Norman ahead at 22% and Graham Nordone at 19%, while later head-to-head surveys showed both candidates with substantial room to grow among undecided Republican voters.
Prediction markets saw Graham Nordone as likely to finish first, but the runoff rules meant “most likely nominee” and “likely primary leader” were never exactly the same bet.
Markets still back Graham
The runoff market is giving Graham Nordone an ever larger edge. Kalshi prices her at 84% on $8.8 million in trading volume, while Polymarket has her at 83% on $1.6 million in trading volume.
That is a much stronger price than she had before the first round, reflecting the assumption that Trump’s endorsement, her interim incumbency, and the Graham name will be enough in a head-to-head contest.
Norman is still the underdog, but he has one thing the other candidates did not: a binary race.
The South Carolina congressman can now consolidate voters who were skeptical of a family succession and uncomfortable with the idea that the appointed incumbent is relying on Trump and Lindsey Graham’s legacy.
His campaign’s best path is to turn the runoff into a referendum on whether voters want a hand-picked successor or a candidate with an independent conservative base.
The Evette warning
The clearest warning sign for Graham Nordone is the South Carolina governor’s race. Lt. Gov. Pamela Evette, initially backed by Trump, was heavily favored in the first GOP primary and still failed to win outright.
She advanced to a runoff and then lost after Trump broadened his endorsement to include both Evette and state Attorney General Alan Wilson.
The parallels are not perfect. Graham Nordone has a stronger family connection to the Senate seat and a clearer direct endorsement, while Norman is a different kind of opponent than Wilson. But the political lesson is the same: A large market lead and a Trump endorsement can get a candidate into a runoff without necessarily getting them through it.
That is why the current 84% price deserves more caution than it would in a normal head-to-head. A runoff has lower turnout, a more motivated electorate, and less room for name recognition alone to carry a candidate. In that environment, the voters who chose Fry, former Gov. Mark Sanford and the rest of the first-round field matter far more than they did two weeks ago.
An endorsement fight begins
The runoff is already becoming an endorsement contest. Trump is reportedly working to make sure Graham Nordone has the political backing she needs, while Norman is pursuing support from conservative groups and elected officials who see an opening to stop the Trump-backed succession candidate.
Evette and South Carolina Sen. Tim Scott, Senate Majority Leader John Thune and Republican Conference Chair Tom Cotton have already backed Graham Nordone, while former Gov. Nikki Haley, Rep. Nancy Mace, Florida Sen. Rick Scott and Utah Sen. Mike Lee have endorsed Norman.
The question is whether Trump’s intervention actually closes the gap or simply makes the race a sharper test of his influence. The Evette result showed that a presidential endorsement is not a substitute for a consolidated campaign, especially when the opposition has a clearer reason to turn out.
South Carolina will almost certainly remain Republican in the general election regardless of who wins August 25. This runoff does not matter much for Senate control. But it matters a lot as a measurement of Trump’s power, the durability of the Graham name and whether prediction markets have properly learned the lesson of a volatile 2026 primary season.
