The Democratic Party wins control of the US Senate in the 2026 midterm elections.
The 2026 midterms will determine legislative power in Washington. Resolves as yes if Democrats secure an outright majority of Senate seats or 50 seats with a Democratic vice president breaking ties.
Across 4 frontier models answering independently, the panel thinks this is unlikely: the median is 31%.
They broadly agree, 21 points between GPT at 37% and Claude at 16%.
Money disagrees. The market sits at 67%, so the models are 36 points less confident than people with cash on the outcome — one of the wider gaps in the archive.
Nothing is settled until 3 Nov 2026, when the outcome is checked against sources and every number above gets a permanent score.
- AI edge
- -36 pts
- Moved this week
- +2 pts
- Since we asked
- +14 pts
- Volume
- $5.5M
The models are sharply less confident than traders risking real money: 31% against 67%.
What each one said
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GPTOpenAI
Democrats need a net gain in a Senate map that likely offers few realistic pickup seats.
openai/gpt-5.6-terra · asked 14 Sept 202637% -
DeepSeekDeepSeek
GOP defends favorable 2026 map; Dems must net 4 seats, historically hard for out-party at midterm.
deepseek/deepseek-v4.1-flash · asked 14 Sept 202633% -
GeminiGoogle
GOP holds 53 seats and VP tiebreaker; Dems need a net gain of 4 with few vulnerable GOP Class 2 targets.
google/gemini-3.8-flash · asked 14 Sept 202629% -
ClaudeAnthropic
Map is brutal for Dems; few GOP seats vulnerable, need net gain of 4 seats
anthropic/claude-sonnet-5 · asked 14 Sept 202616% -
GrokxAIno answer this run x-ai/grok-4.6 · asked 14 Sept 2026–
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QwenAlibabano answer this run qwen/qwen3.8-max-0902 · asked 14 Sept 2026–
4 of 6 models answered · 21 points between the highest and lowest. None was shown the market price.
Resolution criteria
This market will resolve according to the party that wins control of the United States Senate in the 2026 United States midterm election. A party wins control of the United States Senate if it wins a majority of the chamber’s voting seats. If no party wins a majority of voting seats, the party that wins control of the chamber is the party that wins half of the voting seats and holds the Vice Presidency. If the outcome remains ambiguous after applying the above criteria, the chamber will be deemed controlled by the party with which the first selected President Pro Tempore of the Congress that convenes after the specified election is affiliated. The following rules govern the counting of seats for determining which party wins control of the chamber. All regular and special Senate elections that determine representation in the upcoming 120th Congress and are scheduled to take place in November 2026 as of October 31, 2026 are included. Runoffs for qualifying elections will determine attribution of the relevant seat, even if they take place after November 2026. Vacant seats for which no election or special election to fill the seat is scheduled to take place in November 2026 as of Oc
Question sourced from Polymarket on 14 Sept 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.