Scan: Will Democratics win the Senate race in Idaho?

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Will Democratics win the Senate race in Idaho? — Democratic party

SENATEID-26-D · Elections · 2026-04-19

Agent

Market Price

-2.5%

Edge

82%

Confidence

Volume: 31,918

Spread: 4.2c

Days to resolution: 563

Markets in event: 2

Final Rationale

My independent estimate of 2.3% was anchored on Idaho's 0/16 Democratic Senate wins since 1980 and R+30 to R+40 margins, with weak filed Democrats (Roth lost 2022 by 25 points) and no evidence of structural change. I PARTIALLY ACCEPT the critique on information gaps and Risch's age (82, ~6-8% actuarial risk over 18 months) plus the long 563-day horizon — these justify modest widening to ~4%. I REJECT full convergence to the 6.5% market because the market is medium-volatile (2-11% range over 26 days) and the upward drift lacks a surfaced catalyst; the structural case (weak Dem field, no competitive Idaho Senate race in 40+ years, independent Achilles likely splitting anti-Risch vote rather than helping Dems) remains overwhelming. My 4% reflects compound tail scenarios (Risch health event + flawed GOP replacement + national wave + Dem recruit emerging) which must all align.

Price vs. prediction

How the market moved after the agent's call. Solid blue line is the actual market price; dashed line is the agent's static forecast at $t{=}0$.

$n = 58$ follow-ups

1. Planner Opus · Fermi decomposition + tool plan

Tools chosen: article_search web_search kalshi_data wikipedia_lookup code_execution

Sub-questions (Fermi decomposition)

Is Idaho's 2026 Senate race historically competitive enough for a Democrat to win (i.e., has a Democrat won a statewide race in Idaho in the past 20 years)? (w=0.25)
Will the national political environment in 2026 strongly favor Democrats (i.e., will there be a significant Democratic wave that could flip deep-red states)? (w=0.30)
Will the Democratic candidate in Idaho's 2026 Senate race be a strong, well-funded candidate capable of competing in a heavily Republican state? (w=0.25)
Will the Republican incumbent or candidate in Idaho's 2026 Senate race be significantly weakened (e.g., scandal, primary loss, retirement) in a way that gives Democrats an opening? (w=0.20)

Planner reasoning

Idaho is one of the most reliably Republican states in the nation. The last Democrat to win a Senate seat there was Frank Church, who lost his re-election bid in 1980. Since then, Idaho has voted Republican in every presidential and Senate election by large margins (typically 30-40 points). The 2026 Senate race involves either Mike Crapo (Class II seat, up in 2026) or Jim Risch (Class III seat, up in 2028) — need to confirm which seat is contested. Key analytical framework: 1. **Base rate**: Approximately 0% historical success for Democrats in Idaho Senate races since 1980. This is the anchor. 2. **Reference class**: To win, Democrats would need an extraordinary combination of a weakened Republican, a wave election, and an unusually strong Democratic candidate — all simultaneously. 3. **Temporal analysis**: With 563 days until resolution, we are pre-primary. For YES to occur: (a) a credible Democrat must emerge and file (by spring 2026), (b) win or be unopposed in primary (May/June 2026), (c) the national environment must shift dramatically toward Democrats by November 2026, AND (d) the Republican must be significantly weakened. Each step has a low probability; combined probability approaches near-zero. 4. **Wave election consideration**: Even in maximal Democratic wave years (2006, 2008), Idaho remained deeply red. The structural partisanship of Idaho makes it a 'safe Republican' seat in virtually all scenarios. 5. **Kalshi market price** will likely reflect this near-zero probability, providing a calibration check. Expected probability: ~2-4%, primarily reflecting tail risks of catastrophic Republican candidate failure or extraordinary national circumstances.

2. Research Parallel tool calls · legacy v2

Tool	Status	Time	Items
article_search	OK	0.1s	-
web_search	OK	40.5s	-
kalshi_data	OK	1.9s	-
wikipedia_lookup	OK	2.0s	-
code_execution	OK	0.0s	-

3. Evidence Synthesis Sonnet · 13 items · legacy v2

#	Strength	Credibility	Direction	Source	Claim	Priced In
1	STRONG	92	↓ DOWN	code_execution	Democrats have won 0 out of 16 Idaho Senate races since 1980, giving a historical base rate of 0.0% for Democratic wins in Idaho Senate elections.	Yes
2	STRONG	85	↓ DOWN	wikipedia_lookup	Idaho's 2026 Senate seat (Class II) is one of 33 seats contested in 2026; Idaho has been consistently Republican in statewide elections for over four decades.	Yes
3	MODERATE	65	↓ DOWN	kalshi_data	The Kalshi market prices the Democratic candidate's chance of winning Idaho's 2026 Senate race at 6.50%, ranging from 2% to 11% over the observed period.	Yes
4	MODERATE	75	↓ DOWN	wikipedia_lookup	The 2026 Senate elections involve Class 2 seats last elected in 2020; Republicans hold most of these seats but Democrats are defending seats in swing states, making a large Democratic wave structurally difficult.	Yes
5	WEAK	45	NEUTRAL	kalshi_data	No Kalshi market data directly measures the probability of a national Democratic wave in 2026; the Idaho Senate market at 6.50% implicitly incorporates some wave probability but remains deeply pessimistic for Democrats.	Yes
6	WEAK	20	NEUTRAL	article_search	No articles were found assessing the 2026 national political environment or probability of a Democratic wave election.	No
7	MODERATE	72	↓ DOWN	web_search	Three Democrats have filed for Idaho's 2026 Senate race: Nickolas Bonds, Brad Moore, and David Roth (the 2022 nominee who lost), none of whom are widely recognized as high-profile or heavily funded candidates.	No
8	MODERATE	70	↓ DOWN	web_search	Former Democratic state representative Todd Achilles is running as an independent (not Democrat) after resigning from the Idaho House, potentially splitting the non-Republican vote rather than strengthening the Democratic candidate.	No
9	WEAK	50	NEUTRAL	web_search	Idaho Democrats claim a 'historic 2026 slate' with candidates running in all statewide offices and legislative districts, suggesting organizational effort but not necessarily candidate quality or funding competitiveness at the Senate level.	No
10	STRONG	78	↓ DOWN	web_search	Incumbent Jim Risch, 82, is running for a fourth term and faces only minor intra-party challengers (a data engineer, entrepreneur, and engineer); there is no evidence of scandal, major weakness, or credible primary threat that would significantly weaken him.	No
11	MODERATE	75	↓ DOWN	web_search	Risch chairs the Senate Foreign Relations Committee, a position of institutional power that typically aids incumbency and fundraising, further insulating him from vulnerability.	Yes
12	WEAK	40	NEUTRAL	web_search	Risch's age (82) could be a factor in voter concerns or a potential health-related withdrawal, but no evidence of such circumstances has emerged.	No
13	WEAK	30	↓ DOWN	article_search	No articles were found documenting any scandal, controversy, or political weakness affecting Jim Risch or other Republican candidates in Idaho's 2026 Senate race.	No

Information Gaps

No data on fundraising totals or campaign finance filings for Democratic candidates in Idaho's 2026 Senate race — critical for assessing sq3
No polling data available for Idaho's 2026 Senate race to assess current Democratic competitiveness
No data on the national political environment for 2026 — generic ballot polling, presidential approval ratings, or wave election indicators (sq2)
No information on whether any high-profile or nationally recruited Democrat has considered running in Idaho
No data on Idaho's demographic or registration trends that might affect long-term competitiveness
No Cook Political Report or Sabato's Crystal Ball rating for this specific race was surfaced to confirm expert consensus
Unclear if the Kalshi market at 6.50% reflects resolution via a Democrat winning, or if it might be inflated by speculative/low-liquidity trading

Key Uncertainties

Whether Jim Risch's age (82) leads to a health event, withdrawal, or primary loss that creates a genuine opening for Democrats or independents
Whether Todd Achilles running as an independent could split enough Republican/moderate votes to affect the outcome, or conversely drain Democratic-leaning votes
Whether a significant national Democratic wave materializes in 2026, driven by factors such as economic deterioration, Trump administration unpopularity, or major policy failures
Whether any nationally recognized Democrat could be recruited to run in Idaho, dramatically improving candidate quality and funding
Whether the Kalshi price of 6.50% accurately reflects true probability or is inflated due to liquidity premium, speculative positioning, or market inefficiency in a low-volume niche market

Market Context

Price: 0.065 · 7d: -0.005 · 30d: +0.025
Volume: MODERATE — 1,226 average daily contracts is meaningful volume for a state-level Senate race, suggesting some genuine market participation · Depth: MEDIUM
Reliability: MEDIUM — Volume is decent for a niche state market, but the 2-11% price range over 26 days suggests volatility inconsistent with a structurally settled question; the 30-day upward drift (+2.5%) may reflect speculative positioning or new information not yet surfaced, rather than true probability revision. The related 2028 Idaho Republican market at 82% (down 8% in 30 days) is very thinly traded (37 contracts/day) and less reliable.

4. Independent Forecaster Opus · No market price · legacy v2 Did NOT see market price

Independent estimate: 2% (88% confidence)

base rate

90% conf

evidence driven

90% conf

contrarian

85% conf

Spread

1pp

Low disagreement

sq1: Is Idaho's 2026 Senate race historically competitive enough for a Democrat to win?

Base rate: 0/16 Democratic wins in Idaho Senate races since 1980 = 0%. No Democrat has won statewide federal office in Idaho in 40+ years. Margins typically 30-40 points. Slight upward adjustment to 2% for tail scenarios. No evidence of structural change in Idaho's partisanship.

sq2: Will the national political environment in 2026 strongly favor Democrats?

35%

Base rate for midterm favoring opposition party is ~70-75% (since 1934, opposition gains seats in ~36/40 midterms). Trump in second term; historically second-term midterms favor opposition strongly. However, 'strongly favor' implying wave sufficient to flip deep-red states is much rarer — maybe 15-25%. Estimate 35% for significant Democratic lean, but even this wouldn't realistically flip Idaho.

sq3: Will the Democratic candidate be strong and well-funded?

Filed candidates (Bonds, Moore, Roth) are not high-profile. Roth lost 2022 by ~25 points. Todd Achilles running as independent splits opposition. No evidence of major recruiting or fundraising. Base rate for a top-tier Democratic Senate recruit in Idaho is extremely low. Estimate 5%.

sq4: Will the Republican candidate be significantly weakened?

12%

Risch is 82, which adds some non-trivial health/withdrawal risk (~5-8% for someone that age over a ~18-month window). No scandals, strong institutional position as Foreign Relations chair, no primary threat. Even if Risch withdraws, replacement Republican would likely win easily. Estimate 12% for 'significantly weakened' broadly defined, though most scenarios still yield R win.

Show full reasoning trace

base rate: 0 of 16 Idaho Senate races won by Democrats since 1980. Idaho's presidential margins have been R+30 to R+40 for decades. Base rate ~0-2%.

evidence updates: No evidence pushes probability up meaningfully. Risch's age provides slight tail risk but replacement Republican would still likely win. Independent Achilles candidacy could theoretically create chaos but more likely splits anti-Risch vote. Filed Democrats are weak, underfunded.

combination method: Rejecting the literal weighted average because sub-questions measure necessary conditions, not independent paths to YES. Anchoring on historical base rate with minimal upward adjustment for tail scenarios.

final: Idaho Senate seat remains Safe Republican. Probability ~2% reflecting tail risks of health event plus wave plus candidate collapse — all required simultaneously.

ensemble: {'ensemble_count': 3, 'perspectives': {'base_rate': {'p_yes': 0.02, 'confidence': 0.9}, 'evidence_driven': {'p_yes': 0.02, 'confidence': 0.9}, 'contrarian': {'p_yes': 0.03, 'confidence': 0.85}}, 'spread': 0.01, 'individual_p_yes': {'base_rate': 0.02, 'evidence_driven': 0.02, 'contrarian': 0.03}}

5. Devil's Advocate Sonnet · legacy v2 Market price revealed

Overconfidence Missing Info

Challenges

The forecast at 2.3% may be slightly overconfident given 563 days to resolution. With Risch at 82, the actuarial mortality risk alone over 18+ months is ~6-8%, and the forecaster acknowledges this but may be underweighting the compound tail scenarios (health event + special circumstances + wave).
The sq4 reasoning assumes 'replacement Republican would likely win easily' — this is probably true but not certain. Open-seat races in red states CAN occasionally become competitive (see Alabama 2017 with Roy Moore/Doug Jones), especially if a contentious GOP primary produces a flawed nominee. This tail isn't fully priced in.
The forecaster dismisses the market at 6.5% but the market has been drifting UP (+2.5% over 30 days) on moderate volume (1,226 contracts/day). This persistent upward drift despite no surfaced news could indicate information the forecaster is missing (information gaps are explicitly acknowledged — no fundraising data, no polling, no expert ratings).
The combination method explicitly rejects the weighted average in favor of base-rate anchoring. While defensible, this approach minimizes the informational content of sub-questions. Even multiplying rough conditional probabilities (e.g., P(wave)=0.35 × P(Risch weakened)=0.12 × P(strong Dem emerges|those)=0.05 still yields ~0.2%, but allowing for correlations between these events could push to 1-3%).
563 days is a long time horizon with acknowledged major information gaps (no polling, no fundraising, no expert race ratings). This uncertainty should widen the distribution slightly, not narrow it to 2.3% with 88% confidence.

Suggested adjustment: +2pp

Slight upward adjustment from 2.3% to ~4% warranted due to: (1) 563-day time horizon with major acknowledged information gaps, (2) Risch's age creating non-trivial tail risk of open seat, (3) persistent market drift upward suggesting possible information not surfaced in research. Not adjusting fully to market because the structural case for Idaho remaining R is overwhelming — 0/16 base rate, 30-40 point margins, weak Dem field are all correctly weighted.

Market comparison: Forecaster: 2.3%, Market: 6.5%. The 4.2 point divergence is modest and the forecaster's structural reasoning is strong. However, the market's upward drift on moderate volume combined with the forecaster's acknowledged information gaps (no polling, no fundraising data, no expert ratings) suggests the forecast is slightly too confident. Fair value is probably 3-5%.

6. Aggregator Opus · final calibrated forecast

4% (82% confidence)