Democratic Senate Primary Combo: combinatorial overpricing

Executive summary

| | | |---|---| | Position | BUY NO at 33–37¢ | | YES fair value | 14% (range: 6%–25%) | | Edge | +42–46pp | | Conviction | 5/10 | | Key dates | Mar 17 (IL), Jun 2 (IA), Jun 9 (ME), Aug 4 (MI), Aug 11 (MN) | | Settlement | November 3, 2026 (or when two named candidates lose) | | Platform | Kalshi | | Volume | ~$58,000 |

Conviction breakdown: data quality 4/10 (no independent polling in Iowa, limited in Michigan and Minnesota), model confidence 7/10 (the combinatorial structure punishes uncertainty in a predictable, verifiable direction), completeness 5/10 (the Illinois primary on March 17 resolves one of the five remaining inputs within days).

Size conservatively given moderate conviction and soft data in two key races.

-- The market

The contract asks whether at least five of six named Democratic Senate primary candidates will win their respective 2026 primaries. The candidates are James Talarico (TX), Raja Krishnamoorthi (IL), Josh Turek (IA), Graham Platner (ME), Mallory McMorrow (MI), and Peggy Flanagan (MN). The market trades YES at approximately 67¢ as of early March 2026, with $54,000 in volume. It resolves on November 3, 2026, or when two of the named candidates lose their respective primary races.

Talarico won the Texas Democratic primary on March 3, reducing the effective question to whether at least four of the remaining five candidates win. The five remaining primaries span from March 17 (Illinois) to August 11 (Minnesota), meaning the combo could resolve as early as mid-March if Krishnamoorthi loses and one other candidate subsequently loses, or could remain open until late summer.

The order book is thin at the top but fills out at wider spreads. Scaling in may require patience or accepting a wider entry range.

-- The consensus

The market moved from approximately 50¢ to 67¢ in early March, likely reflecting Talarico's confirmed win. That repricing was rational in direction but overshot in magnitude. Talarico's win removed one node of uncertainty, but did not change the underlying field dynamics in any of the five remaining races.

At 67%, the market implies each remaining candidate has an average win probability of roughly 80%. Solving the combinatorial expression P(at least 4 of 5 win) = 5p⁴(1-p) + p⁵ = 0.67 gives p ≈ 0.80 under an equal-probability assumption. The evidence does not support anything close to 80% for any of these races.

The crowd narrative appears to treat these six candidates as the "establishment" or "expected" nominees who will prevail absent a major upset. This framing misreads several of the underlying races, where the named candidates are not frontrunners.

-- The alpha

The methodology is a candidate-by-candidate probability assessment, aggregated through the combinatorial constraint that at most one of the five remaining candidates may lose.

Josh Turek, Iowa — 30%

The Iowa Democratic primary is June 2. Two polls exist, both from interested parties. An NRSC poll conducted February 16-18 among 1,923 likely Democratic primary voters found Wahls at 30% and Turek at 23%, with 42% undecided. The question wording was unfavorable to Turek, pairing him with "backed by Chuck Schumer" against Wahls "aligned with Bernie Sanders." A GQR internal poll released in late February for Wahls showed a larger gap, with Wahls at 42% and Turek at 24%.

Wahls has stronger institutional labor backing from Teamsters Local 90, UFCW Local 1846, and CWA Local 7110, plus national endorsements from former DNC Chairman Howard Dean and former Missouri Secretary of State Jason Kander. Turek's advantages are narrower but real: J.D. Scholten endorsed him and dropped out; Nathan Sage endorsed him and exited in mid-February. A Change Research poll from January found Turek tied with Republican Ashley Hinson at 46% in a general election matchup, while Wahls trailed Hinson 41-48. Electability arguments rarely decide primaries, however, and the DSCC's informal backing of Turek has not translated into public endorsements. With 42% undecided and three months remaining, Turek's primary probability is approximately 30%.

Mallory McMorrow, Michigan — 35%

The Michigan Democratic primary is August 4. The only statewide primary poll is from Emerson College and Nexstar Media, conducted January 24-25 among 491 likely Democratic primary voters. McMorrow led at 22%, with Stevens at 17% and El-Sayed at 16%, and 38% undecided. The RealClearPolling average as of early March shows McMorrow at 23.7%, Stevens at 23.3%, and El-Sayed at 17.3%. This is a genuine three-way race.

Stevens has consolidated significant institutional support: the Michigan Democratic Party Black Caucus endorsement, private DSCC backing, endorsements from former House Speaker Nancy Pelosi, and a slate of Congressional Black Caucus members. El-Sayed carries endorsements from Senator Bernie Sanders and Representative Rashida Tlaib, with a built-in progressive base from his 2018 gubernatorial run. McMorrow's 5-point lead in a fragmented field with 38% undecided five months before the primary is barely directional. Her primary probability is approximately 35%.

Raja Krishnamoorthi, Illinois — 40%

The Illinois primary is March 17. Krishnamoorthi has the fundraising advantage, having raised roughly $25 million (approximately $19.3 million carried over from his congressional fund). The DDHQ polling average, compiled from polls through late January, shows Krishnamoorthi at 34.3% and Stratton at 25.7%.

The most recent data has moved against him. A series of PPP polls commissioned by the Democratic Lieutenant Governors Association shows Stratton's trajectory: 20% in early December, 23% in early February, 27% in late February, 33% in early March (leading Krishnamoorthi 33-30), 32% in the March 9-10 survey (still leading, 32-30). That is a 13-point swing in approximately two months. The March 9-10 PPP poll of 700 likely Democratic primary voters found Stratton at 32%, Krishnamoorthi at 30%, and Kelly at 13%, with 25% undecided. Stratton has consolidated institutional support from Governor Pritzker, Senator Duckworth, Senator Warren, EMILYs List, and the Illinois Federation of Teachers. Krishnamoorthi's favorability dropped from net +36 to net +9 since February, per the DLGA's March release. The non-PPP polling is more favorable (a Tulchin Research poll from mid-February showed him up 42-26; a GBAO internal from late January showed 43-17), but the PPP trend is the most recent data and clearly shows late momentum running against the named candidate. His probability is approximately 40%.

Graham Platner, Maine — 65%

The Maine Democratic primary is June 9. The most recent Pan Atlantic Research poll, released March 4, shows Platner leading Mills 46% to 39% among 367 likely Democratic primary voters, with 11% undecided. This represents a 17-point swing from the same pollster's December survey, which had Mills ahead 47-37. A University of New Hampshire Survey Center poll released in late February found Platner leading 64-26 among 462 likely Democratic primary voters.

Platner outraised Mills by nearly $2 million in the most recent quarter. He dominates among independents who can vote in Maine's semi-open primary (56-23 in the March Pan Atlantic survey) and among voters under 55. Mills retains advantages with voters 55 and older and in the more conservative 2nd Congressional District, and she has DSCC and Schumer backing. Momentum is clearly with Platner. His probability is approximately 65%.

Peggy Flanagan, Minnesota — 55%

The Minnesota DFL primary is August 11. A GQR poll for the Flanagan campaign, conducted January 16-17 among 976 likely DFL primary voters, found Flanagan at 49% and Craig at 36%, with 15% undecided. A broader KSTP/SurveyUSA poll from early February surveyed all registered voters across both parties and found Craig at 20% and Flanagan at 19%, but that was a general electorate survey and is less informative about the DFL primary specifically.

Craig holds a nearly 5:1 cash-on-hand advantage ($3.8 million vs. $811,000). She has committed to contesting the primary regardless of the DFL endorsing convention and has establishment support. Flanagan has Tina Smith's and Senator Al Franken's endorsements, as well as the state's progressive infrastructure. Craig's votes on the Laken Riley Act and an ICE-related resolution have become liabilities among DFL primary voters, with two-thirds of primary voters in the GQR poll saying those votes made them less likely to support her. The race is competitive. Flanagan's probability is approximately 55%.

Aggregation

The combo requires at least four of five to win. With the individual estimates above:

| Scenario | Probability | |---|---| | All 5 win | 0.30 × 0.35 × 0.40 × 0.65 × 0.55 = ~2% | | Exactly 4 win | ~11% | | At least 4 of 5 win | ~12% |

A holistic assessment that allows for modest positive correlation (a national anti-Trump environment lifting all Democratic candidates simultaneously) adds approximately 2 percentage points, yielding a central estimate of 14%.

The range of 6%–25% reflects: the low end (6%) corresponds to Krishnamoorthi losing Illinois on March 17, reducing the margin for error to zero and requiring all four remaining candidates to win. The high end (25%) corresponds to upward adjustments of 10–15 percentage points on each candidate, reflecting a scenario where the analysis systematically underestimates each candidate's strength.

No-Model Test (NMT) sensitivity analysis

"Does the position survive even if the model is wrong?"

| Uniform shift | Combo fair value | Edge vs. 67% | Position | |---|---|---|---| | -10pp | 4% | +63pp | BUY NO | | Base | 12% | +55pp | BUY NO | | +10pp | 26% | +41pp | BUY NO | | +20pp | 42% | +25pp | BUY NO | | +25pp | 56% | +11pp | BUY NO | | +30pp | 67% | 0pp | HOLD |

The position holds under every tested scenario up to a +25pp uniform shift. Breaking even requires adding 30 percentage points to every candidate's estimated win probability — treating Turek as a 60% favorite and McMorrow as a 65% favorite — probabilities inconsistent with the available polling evidence.

-- Risk factors

The thesis could be invalidated by candidates dropping out of races against the named candidates, consolidating the field in their favor. This is most relevant in Iowa, where the field has already narrowed, and in Michigan, where a withdrawal by either Stevens or El-Sayed would dramatically reshape the race depending on where their support flows.

A major national Democratic wave driven by anti-Trump backlash could lift all candidates simultaneously. Morning Consult polling shows Trump underwater in Iowa, Michigan, Minnesota, and Maine. However, a national wave operates through general election dynamics more than intra-party primaries, where the named candidates are competing against other Democrats, not Republicans.

The Illinois primary on March 17 is a near-term catalyst. If Krishnamoorthi wins, the effective question becomes 3 of 4 and the combo's fair value increases to approximately 20–25%. This would narrow the edge but not eliminate it.

Catalysts to watch

Illinois primary result, March 17. A Krishnamoorthi win pushes YES higher, potentially to 25% fair value. Stratton winning resolves one leg and collapses the combo's margin for error to zero, pushing YES fair value down sharply.

Iowa polling, April through May. Any independent public poll of the Iowa Democratic primary would materially update the Turek estimate. Currently, the only two polls are from interested parties.

Michigan field developments. A candidate withdrawal, particularly by Stevens or El-Sayed, would consolidate the field and shift McMorrow's probability depending on which candidate exits and where their support flows.

DFL endorsing convention in Minnesota. If Flanagan wins the DFL endorsement, Craig's willingness to contest the primary may soften, raising Flanagan's probability.

-- Bottom line

BUY NO at 33–37¢. YES fair value is 14%. Edge is approximately 42–46pp. Conviction is 5/10.

The combo structure makes this market extremely sensitive to underdog candidates, and two of the five remaining races feature trailing or narrowly leading candidates in fragmented fields. The NMT table confirms the position holds across all scenarios tested, up to a +25pp uniform shift for all candidates. At a +20pp shift — treating Turek as a 50% coinflip and McMorrow as a 55% favorite — fair value reaches 42%, still 25 points below market price. The Illinois primary on March 17 is the first near-term resolution event and will sharpen the thesis in either direction. Size conservatively given moderate conviction and the soft data environment.