A Republican candidate wins the 2026 U.S. Senate election in South Carolina.
Tracks whether the Republican nominee secures South Carolina's seat in the 2026 U.S. Senate midterms.
Across 6 frontier models answering independently, the panel treats this as close to settled: the median is 97%.
They broadly agree, 6 points between Claude at 98% and Gemini at 92%.
Money disagrees. The market sits at 73%, so the models are 24 points more confident than people with cash on the outcome — one of the wider gaps in the archive.
Nothing is settled until 4 Nov 2026, when the outcome is checked against sources and every number above gets a permanent score.
- AI edge
- +24 pts
- Moved this week
- -9 pts
- Volume
- $566K
The models are clearly more confident than traders risking real money: 97% against 73%.
What each one said
-
ClaudeAnthropic
South Carolina Senate seats have been reliably Republican for decades; 2026 is no exception.
- South Carolina hasn't elected a Democratic senator since 1998 and the state leans heavily Republican statewide.
- Lindsey Graham or another GOP nominee enters as heavy favorite with no competitive Democratic infrastructure in the state.
- Only a major scandal or unprecedented realignment this close to election day would change the outcome, and none is apparent.
98% -
QwenAlibaba
South Carolina is R+17 and hasn't elected a Democrat to the Senate since 1962; this is near-certain.
- SC voted Trump +17 in 2024; no Democrat has won a Senate race there since Fritz Hollings in 1998, and he was a unique incumbent.
- Even Lindsey Graham's closest race (2020 vs. Harrison) was a 10-point win despite record Democratic spending; the structural floor is far higher.
- Only a catastrophic scandal forcing the GOP nominee out with no viable replacement could flip this, which is a <2% tail event.
98% -
GPTOpenAI
South Carolina’s entrenched Republican lean makes an upset require an extraordinary Democratic wave or scandal.
- Republicans have won every South Carolina Senate race since 1998, usually by double digits; the state is firmly red federally.
- Only seven days remain until Election Day, leaving little time for a challenger to overcome the state’s partisan baseline.
- I would cut this sharply if credible late polling showed the Republican nominee below 50% or a major disqualifying scandal emerged.
97% -
DeepSeekDeepSeek
South Carolina is a deep-red state and no Democratic win there is plausible in a normal midterm year.
- Lindsey Graham is the incumbent and SC has not elected a Democrat to the Senate since 1998; Trump won the state by ~18 points in 2024.
- The GOP nominee needs only a plurality under SC's runoff rules, and no serious Democratic challenger has posted competitive polling or funding.
- The one thing that would move this is a Graham loss in a primary runoff to a scandal-plagued challenger, but even then the seat stays Republican.
96% -
GrokxAI
SC's R+ Senate seat is decided six days out with no credible Dem path.
- Graham (or GOP nominee) holds a double-digit polling lead in a state Trump won by 18 in 2024; midterm base rate for R hold here is ~95% since 2004.
- Dems would need a 10+ pt swing plus turnout collapse that has never materialized in SC Senate races.
- Only a late scandal or write-in surge could move it, neither of which is in evidence.
94% -
GeminiGoogle
South Carolina remains an overwhelmingly conservative state where no Democrat has won a statewide race since 2006.
- Incumbent Lindsey Graham won by 10 points in 2020 despite record-shattering $130M+ fundraising by Democrat Jaime Harrison.
- Federal midterms under an opposing or same-party presidency historically do not overturn double-digit structural party margins here.
- Only an extraordinary personal scandal or an independent conservative splitting the vote could put this seat in jeopardy.
92%
6 of 6 models answered · 6 points between the highest and lowest. None was shown the market price.
Resolution criteria
This market will resolve according to the winner of the 2026 midterm South Carolina U.S. Senate election, inclusive of any run-offs. A candidate shall be considered to represent a party in the event that he or she is the nominee of the party in question. Candidates other than the Democratic or Republican nominee (e.g., Greens, Libertarian, independent) may be added at a later date. Candidates who run as independents will not be encompassed by the “Democrat” or “Republican” options regardless of any affiliation they may have with the party. The candidates may be named in the contract for the convenience of traders. In the event that any named candidate is replaced as the nominee of their respective party prior to election day, the name in the contract will be updated and the market will resolve based on the replacement nominee of the party. The resolution source for this market is the Associated Press, Fox News, and NBC. This market will resolve once all three sources call the race for the same candidate. If all three sources haven’t called the race in this state for the same candidate, this market will resolve based on the official certification.
Question sourced from Polymarket on 28 Oct 2026. Forecast by google/gemini-3.8-flash, anthropic/claude-sonnet-5, openai/gpt-5.6-terra, x-ai/grok-4.6, deepseek/deepseek-v4.1-flash, qwen/qwen3.8-max-0902 via OpenRouter.