Scan: Will the Democrats win the Maine Senate race in 2026?

date	predicted	market price	confidence
2026-08-29	62%	70%	46%
2026-08-22	60%	70%	53%
2026-08-15	61%	70%	56%

1. Planner Fable 5.1 · Fermi decomposition + tool plan

Tools chosen: polymarket_direct kalshi_related polymarket_related article_search claude_news gdelt_news wikipedia code_execution

Sub-questions (Fermi decomposition)

What is the current Polymarket and Kalshi price for Democrats winning the 2026 Maine Senate seat, and how has it trended?
Is Susan Collins definitively running for re-election, and what is her current approval/favorability among Maine voters?
Who is the likely Democratic nominee (Janet Mills vs. Graham Platner) after the June 2026 primary, and what do head-to-head polls against Collins show?
What do the most recent public polls (last 60 days) show for Collins vs. the Democratic nominee, and what is the polling average margin?
What is the national midterm environment (generic ballot, presidential approval) and how does it historically translate to Senate races in states won by the opposing party's presidential candidate?
Are there significant independent or third-party candidates that could split the anti-Collins or anti-Democratic vote, and how does Maine's ranked-choice voting affect the outcome?
How do forecasters (Cook, Sabato, Inside Elections) rate the race, and what is the base rate for incumbents surviving in crossover states in midterms unfavorable to the president's party?

Planner reasoning

This is a Polymarket election market on the 2026 Maine Senate race, where Republican incumbent Susan Collins is running in a Biden/Harris-won state. Key drivers are the Democratic nominee (Janet Mills vs Graham Platner primary in June 2026), Collins's approval and fundraising, polling, and the national midterm environment. Market prices on Polymarket and Kalshi provide the anchor; news, polling, and background fill in the rest.

2. Research Parallel tool calls

tool	status	time	items	summary
polymarket_direct	OK	0.5s	1	## This Market's Polymarket Data Will the Democrats win the Maine Senate race in 2026? - Current price (probability): 70.50% - 7-day price change: +0.00% - 30-day price change: +1.00% - Total volume: $809,712 (USD notional) - Price range: 52.50% - 72.50% - Data points: 90 days
kalshi_related	OK	16.1s	2	2 related markets / summaries. keyword 'Maine Senate': ok \| keyword 'Collins': no matches \| keyword 'Maine Senate 2026': ok
polymarket_related	OK	0.2s	0	Scanned 100 active Polymarket markets, kept 0 matches. keyword 'Maine Senate': 0 markets \| keyword 'Collins': 0 markets \| keyword 'Platner': 0 markets \| keyword 'Mills Senate': 0 markets
article_search	OK	46.6s	21	Fetched 21 unique articles across 4 queries (lookback=60d). 'Maine Senate race 2026 poll Collins': 10 articles \| 'Graham Platner Janet Mills Democratic primary Maine Senate': 10 articles \| 'Susan Collins reelection approval Maine 2026': 10 articles \| 'Cook Political Report Maine Senate rating': 10 a
claude_news	OK	25.3s	17	## Key Findings: 2026 Maine U.S. Senate Race - Candidates finalized: Incumbent GOP Sen. Susan Collins, seeking a sixth term, faces Democrat Troy Jackson (former Maine Senate president), not Janet Mills or Graham Platner. Graham Platner won the Democratic primary over Governor Janet Mills with
gdelt_news	OK	153.4s	10	GDELT: 10 articles across 3 queries (lookback=30d). 'Susan Collins Senate 2026': error GDELT rate-limited after retries (429) \| 'Maine Senate race poll': 10 hits \| 'Graham Platner': error GDELT rate-limited after retries (429)
wikipedia	OK	0.3s	4	Fetched 4 Wikipedia entries (0 missing pages).
code_execution	OK	61.9s	0	Base‑rate / model results — Maine Senate 2026 (Collins‑R incumbent, Trump‑era midterm, Harris‑won state) - Historical crossover‑incumbent sample (n=8): Looking at Senate incumbents from the president's party running in a state the opposing presidential candidate carried (2006: Chafee‑RI, Sa

3. Evidence Brief Sonnet 5 · 7584 chars

# Current state Democrat Troy Jackson (replacing withdrawn nominee Graham Platner) faces GOP Sen. Susan Collins in November 2026; recent polling (Aug–Sep 2026) shows a true toss-up with Jackson holding narrow, within-MOE leads in most surveys, while Collins has historically outperformed polls in Maine. No Kalshi-direct price was returned in research; Polymarket price (70.5% Dem) is used as primary market anchor. # Timeline of key events - 2025-08: Graham Platner announces Senate campaign, gains progressive momentum (Wikipedia). - 2025-10 to 2026-04: Gov. Janet Mills runs against Platner for Dem nomination, then suspends campaign in April 2026 (Wikipedia, claude_news). - 2026-02-10: Susan Collins confirms 2026 reelection bid — confirmed (bangordailynews.com). - 2026-06-04: UMass Lowell poll shows Platner with slight lead over Collins pre-primary — confirmed poll. - 2026-06-09: Primary — Collins unopposed for GOP nod; Platner wins Dem primary over Mills — confirmed (Wikipedia). - 2026-07-10: Platner withdraws following rape allegation (denied) and other controversies — confirmed (Wikipedia). - 2026-07-25: Maine Dem convention selects Troy Jackson as replacement nominee — confirmed (CBS News, Wikipedia). - 2026-07-27: NPR reports Jackson formally on ballot, race rated toss-up/lean-D by outlets — confirmed. - 2026-08-06/10: Fox News poll: Jackson 48%–46% lead — confirmed poll; UNH poll (7/15-20): Jackson 49%-46% — confirmed poll. - 2026-08 (late): Poll shows Jackson +3 among likely voters (48-45), Collins +1 among all registered voters (46-45) — reported, mixed samples. - 2026-09-08/10: Rasmussen poll shows sharply partisan split; Jackson leads among unaffiliated 48-36 — confirmed poll. - 2026-09-09: CNN/SSRS poll: Jackson 48%, Collins 45% ("neck-and-neck") — confirmed, widely reported (BDN, CentralMaine, PressHerald, WABI). # Event Will the Democrats win the Maine Senate race in 2026? # Outcomes to forecast - Yes (Democrat/Troy Jackson wins) - No (Republican/Susan Collins wins) # Kalshi market anchor No direct Kalshi price was returned for this specific ticker in research (kalshi_related search found only unrelated 2028 Senate-control markets, not this Maine race). **Primary available market anchor: Polymarket price = 70.5% YES (Dem win)**, flat over 7 days, +1pt over 30 days, range 52.5%–72.5% over 90 days, $809,712 volume — this suggests the market has drifted up but remains well above recent polling parity, likely reflecting confidence in Maine's Dem lean and skepticism of Collins given the crossover-state dynamic. # Sub-question answers 1. **Polymarket/Kalshi pricing & trend** — Polymarket: 70.5% Dem, flat 7d, +1pt 30d, historical range 52.5-72.5%. No Kalshi-specific price found (polymarket_direct). 2. **Is Collins running? Approval** — Yes, confirmed reelection bid announced Feb 10, 2026 (bangordailynews.com). No specific recent approval numbers found in research beyond horse-race polling. 3. **Democratic nominee** — Neither Mills nor Platner; Troy Jackson (former state Senate president) is the actual nominee after Platner's July 10 withdrawal amid sexual assault allegations and Mills' earlier suspension (Wikipedia, CBS News). 4. **Recent polls (last 60 days)** — CNN/SSRS (9/9): Jackson 48-45; Fox News (8/6-10): Jackson 48-46; UNH (7/15-20): Jackson 49-46; Rasmussen (9/8-10): heavily partisan split favoring Jackson among independents 48-36. Polling average: Jackson leads by ~2-3 points, within margin of error (claude_news, gdelt_news). 5. **National environment** — "Historically unpopular president" and bad economy cited as headwinds for GOP; generic ballot/tariff sentiment (70% of Maine voters view Trump tariffs negatively) favors Democrats (claude_news). Historical base-rate model (code_execution): crossover incumbents (president's-party senator in opposing-party-won state) lost 8/8 historical cases (100%), smoothed to ~83% loss probability — though Collins is a noted outlier. 6. **Third-party/RCV effects** — No significant third-party candidates identified in research; Maine's ranked-choice voting is noted as complicating pollster methodology (need for second-choice data) but no major independent contender flagged (Newsweek via claude_news). 7. **Forecaster ratings & base rates** — Cook Political Report and Sabato's Crystal Ball both rate the race a toss-up (Newsweek/claude_news). Code_execution model: naive base-rate+polling blend ≈67% Dem win, but adjusted for Collins' unique history of outperforming fundamentals (won by 9 in 2020 despite Biden +9), judgmental estimate narrows to ~35-45% Dem win. # Key facts (high-confidence, factual) 1. [Wikipedia] Troy Jackson is the confirmed Democratic nominee; Collins unopposed for GOP nomination. 2. [Wikipedia] Collins is the only GOP senator from a state Trump never carried in three campaigns. 3. [CBS/claude_news] Republicans reserved $42.6M in ad time for Collins vs. $9.7M reported for Democrats (as of Feb 2026). 4. [claude_news] Democrats haven't won a Maine Senate seat since 1988. 5. [claude_news] In 2020, Collins won by 9 points despite Biden carrying Maine by 9 — largest documented crossover overperformance in the sample. 6. [Multiple polls, Sep 2026] Jackson leads Collins by 2-3 points in most recent public polls, within MOE. # Cross-market signals - Kalshi related: No direct match found; unrelated 2028 Senate-control markets priced 50-57% Dem, not informative for this race. - Polymarket: 70.5% Dem win, stable, moderate-high volume ($810K), suggesting sustained market confidence above raw polling parity. - Sportsbook implied: None found. # Analyst opinions and speculation - Cook Political Report / Sabato's Crystal Ball: toss-up rating (claude_news/Newsweek). - Code_execution model: judgmental range 35-45% Dem win after discounting for Collins' idiosyncratic strength — notably below the 70.5% Polymarket price, flagging a potential market/analyst divergence. - NPR: women voters and abortion politics (Collins' Kavanaugh vote) seen as pivotal given post-Dobbs environment. # Directional lean per outcome - **Yes (Dem/Jackson)**: Supported by consistent (if narrow) polling leads, unfavorable national environment for GOP, blue-leaning state fundamentals, heavy ad spending gap not yet decisive. Opposed by Collins' unmatched history of overperforming polls/fundamentals (2020 precedent) and late/rocky Dem nominee transition (Jackson replacing scandal-hit Platner). - **No (Collins/GOP)**: Supported by 100% historical base rate discount, Collins' 30-year incumbency brand, and 2020 precedent of beating polls by ~18pts relative to fundamentals. Opposed by first post-Dobbs cycle, Trump/tariff unpopularity, and consistent Jackson polling edge. # Gaps / unknowns - No direct Kalshi price found for this exact ticker in research — must rely on Polymarket as anchor, introducing platform-basis risk. - No explicit approval rating figures for Collins found. - Uncertain how RCV second-choice allocations from minor candidates could shift the top-two margin. - No polling after Sep 10, 2026 captured; race could shift closer to election. # Calibration anchors - Polymarket (proxy anchor): 70.5% YES (Dem win), stable trend. - Code_execution judgmental estimate: ~35-45% Dem win (notably below market). - Historical crossover-incumbent base rate: ~83% loss for GOP incumbent (unadjusted); heavily discounted for Collins' idiosyncratic strength. - 2020 Maine Senate precedent: Collins outperformed polls/fundamentals by ~9-18 points — key calibration caution against over-relying on current polling leads for Jackson.

4. Forecasters Fable 5.1 + GPT-5.6 Sol · in parallel

claude-fable-5-1

54% conf

Yes	63%
No	37%

The primary market anchor (Polymarket, no direct Kalshi price) sits at 70.5% for a Democratic win, consistent with recent polls (CNN/SSRS 48-45, Fox 48-46, UNH 49-46) showing Jackson with a narrow but persistent lead, a midterm environment hostile to the GOP (unpopular president, tariff backlash), and Maine's blue lean. However, Collins is the single strongest crossover overperformer in modern Senate history (won by 9 in 2020 while Biden carried Maine by 9), Cook and Sabato both rate the race a toss-up, Republicans hold a large ad-reservation advantage, and Jackson is a late replacement nominee after the Platner scandal—all reasons to discount the market somewhat. Blending the ~70% market with the toss-up ratings and Collins' polling-beating track record, I land modestly below the anchor at ~63% Yes.

gpt-5.6-sol

68% conf

Yes	66%
No	34%

The 70.5% Polymarket YES price is the best available consensus anchor because no direct Kalshi price was found. Jackson's consistent 2–3 point polling leads, strength among unaffiliated voters, Maine's Democratic lean, and an unfavorable national environment for Republicans point toward Yes. However, the leads remain within sampling error, major forecasters call the race a toss-up, and Collins won by nine points in 2020 despite Biden carrying Maine by nine, demonstrating exceptional crossover strength. I therefore shade the Democratic probability below the market anchor while retaining Jackson as the clear favorite.

5. Devil's Advocate Sonnet 5 · red-team critique

Both forecasters anchor heavily on Polymarket (70.5%) despite the brief explicitly flagging a "potential market/analyst divergence" — the code_execution judgmental model puts Dem win at only 35-45%, roughly half the market price — yet neither forecast seriously grapples with why the market might be wrong (e.g., low-information retail bettors, thin true price discovery for a niche state race) versus why their own toss-up-consistent polling should dominate.

Both converge to nearly identical outputs (63% and 66%) despite citing the same toss-up ratings from Cook/Sabato, which by definition imply ~50%, not 63-66%; neither explains why they weight the market anchor so much more heavily than the explicit toss-up consensus from professional election forecasters.

Neither forecast adequately incorporates the $42.6M vs $9.7M ad-spending disparity (a ~4:1 gap) as a forward-looking factor — this spending will disproportionately land in the final stretch before Nov 3 and could erode Jackson's narrow 2-3pt lead, especially given Collins' history of gaining ground late.

The 2020 precedent (Collins winning by 9 despite Biden+9, an 18-point swing from partisan lean) is mentioned by both but not quantitatively applied — if even half that swing occurred in 2026, Jackson's 2-3pt polling lead would convert to a Collins win, yet both forecasts still land at 63-66% Yes, effectively underweighting this single most relevant historical data point for this exact race/candidate.

Neither forecast addresses the RCV/methodology uncertainty flagged in the brief ("need for second-choice data... complicating pollster methodology") or the lack of any post-Sept 10 polling, both of which add meaningful uncertainty that should widen error bars rather than support high-confidence stated (0.54 and 0.68).

The Jackson candidacy itself (late replacement for scandal-hit Platner, unclear statewide name recognition/fundraising infrastructure) is listed as a headwind in the brief but isn't distinctly modeled—both forecasts treat Jackson's polling numbers as if he were a fully battle-tested nominee, when a late substitute nominee historically carries elevated variance/downside risk not captured in current toplines.

6. Aggregator Fable 5.1 · final calibrated forecast

58% (61% confidence)

Yes: 58% No: 42%

The Polymarket anchor (70.5%) is the only market signal, but the critique correctly notes it sits well above what the underlying evidence supports: professional forecasters rate the race a pure toss-up, Jackson's 2–3 point polling leads are within sampling error, and Collins beat her 2020 polling average by roughly 9 points in this exact state — a swing that would more than erase Jackson's current edge if even partially repeated. Additional downside factors both forecasters underweighted include the ~4:1 GOP ad-reservation advantage that will land in the final stretch, Jackson's status as a late replacement nominee with an untested statewide operation, and RCV/methodological uncertainty in the polls. Counterbalancing this, the national environment (unpopular president, tariff backlash, post-Dobbs abortion salience), Maine's blue lean, Jackson's strength among unaffiliated voters, and the near-perfect historical loss rate for crossover incumbents keep the Democrat a modest favorite. I therefore move below both forecasts toward the toss-up ratings while still giving Jackson the edge, landing at 58% Yes.

7. Entry Decision Fable 5.1 trader

Side

no

Position Size

$700

Contracts

2333

Trader Confidence

61%

Trade rationale

The forecast lands at 58% Yes versus a 70.5% market, a -12.5% edge pointing to NO. Both the bot and the market agree the Democrat is the favourite, so this is a magnitude disagreement rather than a directional one, which is a weaker signal class — but the rationale does point at concrete, forward-looking items the market may be underweighting: the ~4:1 GOP ad-reservation advantage that lands in the final seven weeks, Jackson's status as a late replacement nominee with an untested statewide operation, and the fact that Cook/Sabato toss-up ratings historically correspond to ~50-60% prices, not 70%. Collins beating her 2020 polling average by ~9 points in this exact race is a strong candidate-specific prior for polling error running against the Democrat. The Devil's Advocate critique cuts in favor of the NO side (it argues the ensemble anchored too heavily on the market), so it reinforces rather than undermines the trade. Forecaster confidence at 0.61 is middling and does not move the decision.

Allocation logic

Sized at $700, below baseline, because this is an against-favourite bet in the 0.70-0.80 band (mixed 5/4 record), the bot itself still rates the Democrat as the likely winner, and the book already holds a correlated anti-Democratic position (NO on 'Blue wave in 2026') — the 12.5% edge justifies entry but not a full-size position.

Entry price: $0.30

Current: $0.40

Status: OPEN

P&L: $202.07

Pipeline Timing

Total pipeline time: 265.9s

Per-tool research timings shown in the Research section above.