Analysis

    South Carolina's Senate Special Primary Is Today. Here's What Prediction Markets Say.

    South Carolina Republicans vote today in a special primary to replace the late Lindsey Graham. What prediction markets say about tonight and November.

    By Prediction Markets US Analysis DeskTuesday, August 11, 20267 min read
    South Carolina's Senate Special Primary Is Today. Here's What Prediction Markets Say.

    South Carolina Republicans head to the polls today in a special primary to pick a replacement for the late U.S. Senator Lindsey Graham, whose sudden death last month set off a compressed three-week race among ten candidates — and kicked off one of the most actively traded Senate prediction markets of the 2026 cycle. With $4.8 million on Kalshi alone, the market has already spoken. But tonight's results may not be the end of it.

    The Race That Wasn't Supposed to Happen

    Lindsey Graham died on July 11, 2026, after suffering a tear in his aorta at his Washington home — barely a month after winning the South Carolina Republican primary for his fifth Senate term. The timing was jarring: Graham had easily dispatched challengers in June and was preparing for a November general election against Democrat Annie Andrews, a pediatrician from Charleston. His death required the state Republican Party to start over.

    Governor Henry McMaster moved quickly. On July 13, he appointed Darline Graham — Lindsey's younger sister — to serve as interim senator for the remainder of the term, which runs through January. She was sworn in July 14. Two days later, with President Donald Trump's encouragement, she announced she would seek a full six-year term.

    Under South Carolina law, when a candidate who has already won a party primary dies before the general election, a special primary must be held to select a replacement nominee. Ten Republicans filed for the August 11 contest. If no candidate clears 50 percent of the vote today, the top two finishers advance to a runoff on August 25. The winner faces Andrews on November 3.

    What the Markets Say About Today's Vote

    Kalshi has hosted roughly $4.8 million in trading volume on the South Carolina Republican Senate special primary winner market — one of the largest single special-election books the exchange has listed, according to reporting from OddsShopper. As of this morning, the market stood at:

    CandidateKalshi (Aug 11, 10 AM ET)Polymarket Global
    Darline Graham Nordone41–42¢45.8%
    Ralph Norman32–33¢25%
    Russell Fry21–22¢26.2%
    Mark Sanford3–4¢~2.5%
    All others<1¢ each<1% each

    Polymarket prices shown are from the global polymarket.com platform. Kalshi is the primary CFTC-regulated U.S. exchange offering South Carolina Senate election markets.

    Graham entered as the prohibitive favorite when she announced, but her odds have drifted as polling tightened. A late Emerson College poll showed Norman at 22 percent and Graham at 19 percent among likely voters — with roughly a quarter of the electorate still undecided, suggesting significant late-breaking movement is possible. Kalshi's price decline from the high 50s to the low 40s over the past week reflects the same tightening.

    There is one thing both markets agree on: an outright first-round winner is unlikely. A separate Polymarket market on "first round outright winner" priced the probability of any candidate clearing 50 percent tonight at just 7 percent. South Carolina law requires that majority threshold; if no one hits it, the race continues to August 25.

    The Candidates

    Darline Graham Nordone is serving as interim senator and carries Trump's endorsement — a significant advantage in a South Carolina Republican primary. She has campaigned on continuing her brother's legacy, particularly his foreign policy work, and enjoys name recognition that most of her rivals can't match. A pro-Graham super PAC spent $900,000 on her behalf.

    Ralph Norman, a sitting U.S. Representative with a statewide profile from his 2022 governor's race, has secured endorsements from Senators Rick Scott and Mike Lee. His support among fiscal conservatives and the MAGA wing of the state party has made him the most consistent second-place finisher in polling, and prediction markets now put him within striking distance.

    Russell Fry, another sitting congressman representing the Myrtle Beach area, entered the race without Trump's backing despite early indications he might receive it. He has a smaller geographic base than Norman but performed strongly in the lone debate.

    Mark Sanford, the former governor and former congressman who served in both roles, rounds out the top tier at single-digit odds. His comeback bid has found limited traction in a compressed campaign.

    The General Election Picture

    Regardless of who wins the Republican nomination, the November 3 general election looks difficult for Democrat Annie Andrews.

    Live market view — track these prices yourself:

    South Carolina has not elected a Democrat to any statewide office in two decades. Nonpartisan race ratings uniformly classify the November contest as Solid or Safe Republican. On Polymarket's global platform, Republican wins the general election at 91 percent, with Democrat at 10 percent — pricing that has barely moved throughout the entire campaign.

    Even so, the race matters. Graham was viewed as a dependable vote for the Republican majority. His death opened a question: would the seat remain as safe under a different nominee? The market's answer has been yes — but the primary fight itself shows how competitive Republican politics in the state has become.

    Senate Control: What South Carolina Means for November

    South Carolina's Senate seat may be a near-certain Republican hold, but the national picture for chamber control is far less settled.

    Live market view — Senate control:

    On Polymarket's predictions page, the Senate control market shows Republicans with a 54 percent chance of retaining their majority. Democrats have roughly 46 percent. The Kalshi balance-of-power board prices a full Democratic sweep (House and Senate) at 44 cents, with a split Congress — Democratic House, Republican Senate — at 39 cents.

    South Carolina's role in that calculation is straightforward: keeping it in the Republican column is table stakes. What makes tonight interesting is who holds the seat. A divided or harder-to-predict nominee from today's vote could create unexpected drag in a race that both parties are already mapping aggressively toward November.

    What Happens Next

    • Tonight: Polls close. Results begin reporting. Markets reprice in real time.
    • If no one hits 50%: The top two finishers move to an August 25 runoff. Given polling fragmentation, this is the base case — markets price it at 93 percent probability.
    • August 25: Runoff determines the Republican nominee. This is where the prediction market odds suggest the real race will be decided.
    • November 3: The nominee faces Annie Andrews in the general election.

    For prediction market traders, the interesting action is in the primary itself. The Graham vs. Norman vs. Fry three-way creates genuine uncertainty across all price points. Graham at 41 cents implies a 59 percent miss chance; Norman at 32 cents is still live; Fry at 22 cents is the long shot that held up better than field candidates in polling.

    FAQ

    When will we know who won? South Carolina's results typically report quickly on primary nights. If one candidate clears 50 percent, the Kalshi market settles tonight. If not, settlement awaits the August 25 runoff.

    What is a special primary and why is it needed? When a primary winner dies before the general election, South Carolina law requires the party to hold a new primary to select a replacement nominee. Lindsey Graham won the Republican primary in June and died in July — triggering today's special election. The winner replaces Graham on the November ballot.

    Does it matter who wins the primary for the general election? Prediction markets say no, at least in terms of the ultimate outcome: Republican 91 percent in the general regardless. But the identity of the nominee affects whether the new senator arrives in Washington with a debt to Trump or to the congressional establishment — a distinction that could matter for the legislative dynamics of the next Senate term.

    Can US users trade these markets? South Carolina Senate markets are available on Kalshi, which is regulated by the CFTC and operates as a federally licensed exchange. Kalshi is accessible in most U.S. states. Polymarket's global platform lists the same markets but operates outside the direct U.S. regulatory framework for domestic users.

    Conclusion

    The race to replace Lindsey Graham has compressed a year of normal Senate campaign dynamics into three weeks. Tonight's special primary delivers the first definitive data point: whether a Trump endorsement and the Graham family name can hold off two sitting congressmen in a crowded field.

    Whatever happens, the prediction markets have been ahead of the story — and will update the moment results come in. Track all the live odds at PredictionMarkets.US.

    Sources & Verification

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