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FORECAST51 DAYS OUT
← Senate3 November 2026 · 51 days out

Kansas · U.S. Senate

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Roger Marshall is favored to hold Kansas’s Senate seat. Predicted margin: R+8.1.

Adam Hamilton (D)14 in 10014.0%43.9high 48.6 · low 39.2
Roger Marshall (R)86 in 10086.0%51.6high 56.3 · low 47.0

high / low: vote share (%) in the middle 80 in 100 simulations

About this field

Not competitive.

Forecast share averages the simulated vote. Win chance counts how often a candidate wins. A wider range of outcomes can give a candidate a higher win chance despite a lower average share.

Likely R80% range · margin points R+17.9 to D+1.7Republican-held seat

Forecast history

Moving D · mild+0.9 pts · Sep 11 → Sep 13
Aug 1Nov 3 · Election Day

Latest reading · Sep 13 · first published Sep 9 · 80% range · margin points R+17.9 to D+1.7. Methodology

Hover the line, tap it, or use the arrow keys to inspect its history.

About this series

This comparable series begins on September 9, 2026, when the model version changed to CTMM 2.2. Earlier readings remain in the archive and are not joined as voter movement; faded points before September 9, 2026 are reconstructions, not forecasts issued on those days.

Faded: CTMM 2.2 reconstructed history: computed after the fact with each date's available polls and environment, without expert ratings; not an issued forecast. Issued forecasts begin at the launch marker.

The polls

Ledger weighted average R+2.0Used by the forecast: 5 polls (60-day half-life) · measured R+4.6 · after the fitted poll-error shift R+6.15 recorded polls · 5 eligible for the aggregate · 5 with positive weight

FieldworkAddedPollsterResultSample
from 2026-09-081h agoco/efficient ↗R+5.0D 44% · R 49%915 LV
from 2026-08-12Global Strategy Group ↗People Over Politics Action FundD+1.0D 44% · R 43%800 LV
from 2026-08-07Public Policy Polling (D) ↗Senate Majority PACR+1.0D 45% · R 46%569 LV
from 2026-07-08GBAO ↗R+4.0D 43% · R 47%600 LV
from 2026-01-26Tavern Research ↗R+8.0D 46% · R 54%1,013 LV
Explore poll adjustments

5 of 5 matching · 5 total

Ledger weighted average R+2.0

co/efficient10 Sep · 915 LV · added 13 Sep
Global Strategy Group16 Aug · 800 LV · added 5 Sep
Public Policy Polling (D)8 Aug · 569 LV · added 14 Aug
GBAO13 Jul · 600 LV · added 19 Aug
Tavern Research28 Jan · 1,013 LV · added 19 Aug
Explore all 5 polls for this race

How the margin was built

Follow each contribution to the margin. Wider ribbons mean more percentage points. Tap an input for its calculation and source.

Toward D+9.0
Toward R−17.1
Forecast marginR+8.1

The signed totals combine at the forecast. Displayed values are rounded.

All calculations & sources

How this state voted, 2024 −16.120 points

The state's two-party presidential margin in 2024, from our own county sums — the same measurement the model's statewide terrain center is built from. Every pull below is measured from here, not from EVEN, which is why a landslide seat's listed pulls are small numbers and still land where the forecast does.

  • 2024 presidential result for this state, two-party, from Call the Map's own county sums.
  • Same source as Act I's 2024-president reference mark, so the origin lands on it.

This race’s polls +4.116 points

What this race’s own recent polling adds beyond its prior, after each poll is weighted for recency, sample size and pollster quality.

  • 5 matchup-validated, sample/recency/grade-weighted poll(s), latest 2026-09-10
  • Global Strategy Group (2026-08-16, n=800): D+1.0 · weight 0.49
  • Public Policy Polling (D) (2026-08-08, n=569): R+1.0 · weight 0.32
  • GBAO (2026-07-13, n=600): R+4.0 · weight 0.14
  • Tavern Research (2026-01-28, n=1,013): R+8.0 · weight 0.00
  • Adjusted poll-bank aggregate R+2.0 · 4 recorded polls · 4 eligible for the aggregate · 4 with positive weight. The sealed model records a net polling contribution of +4.1 D. Observation weights are not the final model blend weight. Eligible polls: latest poll: 2026-08-16 (28 days old).
  • Adjusted poll-bank aggregate R+2.0 · 4 recorded polls · 4 eligible for the aggregate · 4 with positive weight; recorded polling contribution +4.1 D. These observation weights must not be read as the model’s final prior-versus-polling weight. Eligible polls: latest poll: 2026-08-16 (28 days old).

Fitted model, above the terrain shown +2.850 points

What the fitted model adds on top of the starting terrain above — incumbency, past results, campaign finance and the other fitted terms — measured from that terrain rather than from EVEN. It is a comparison with the starting point already shown, not a separate input. The source detail lists the variables the fit uses.

  • Fitted baseline -13.270 minus starting point -16.120 = 2.850 points.
  • For orientation, the presidential results here: 2024 R+16.1, 2020 R+14.8.
  • The work: the −13.3 D fundamentals push is the sum of the dynamic formula's surviving variables for this race — each one's own contribution is listed below.
  • fundamentals core = 25-term dynamic formula (mass fit over the master feature matrix, held-out-cycle validated; see matrix/feature_dictionary.md + mass_fit_report.json)
  • 9-term formula, held-out validated.

National environment +1.988 points

The contribution to this race’s margin, not the national polling margin itself. The race’s loading, reference level and polling blend determine how much of the national climate reaches its final forecast.

  • Three-source blend, updated 2026-09-08: 52% generic-ballot aggregates (D+6.5) · 28% special-election overperformance (D+9.0 across 46 specials) · 20% approval-implied (D+8.6 from net approval -21.7).
  • Latest polls — generic ballot 2026-09-08 (5 days old), approval 2026-09-10 (3 days old).
  • Generic-ballot average D+6.5 · support factor 0.84 (the share of that channel's capacity the admitted polls carry) — separate inputs; their product is a capacity diagnostic, not a margin.
  • Weights are the 55/25/20 capacities scaled by each channel's evidence and renormalized, so thin polling widens the interval instead of pulling the center toward zero — 16% of the weight is carried that way.
  • Blended national environment: D+7.6.
  • Applied at full strength to this chamber's races.
  • The work: national environment × 1 chamber strength = +2.0 D of this margin.
  • Blended national environment: D+7.6 (updated 2026-09-08).
  • Effective poll weight 84%; fundamentals share 16%, carried by the interval (×1.08) rather than by the center.
  • The support factor is the share of the generic-ballot capacity the admitted polls carry; average × support is a capacity diagnostic, not a margin, and is not what the row above multiplies.
  • Applied at full strength to this chamber: +2.0 of this margin.

Structural safeguards −0.950 points

Bounded corrections that keep the model consistent with structural facts.

  • Applied only when a safe state's dynamic fundamentals point in the same direction as its strong presidential lean but are materially compressed toward zero.
  • The 25% correction toward that lean improved safe-race MAE in strict expanding-window validation without changing a historical call.
  • The disclosed adjustment is −0.9 D.

The components this edition publishes for this race, in points. “Other factors” closes the sum to the two-party structural lean exactly. Here the structural lean IS the published margin, so the walk sums to the projection exactly; nothing is left over.

Named factorContribution
FundamentalsThe admitted fitted baseline. Its surviving variables differ by office; the source detail above identifies those used for this race.−13.27
This race's pollsAdmitted head-to-head polls of this race, recency- and quality-weighted.+4.12
National environmentThe national environment’s contribution to the prior. Polling can attenuate its influence; this value is not the national polling margin.+1.99
Structural terrain safeguardA bounded pull toward presidential terrain in heavily partisan states.−0.95
Other factors0.00

Recent elections

ElectionResultVotes cast
2020 · U.S. Senate ↗R+12.01,367,755
2014 · U.S. Senate ↗Not a D–R contestThe ballot was not a Democrat versus a Republican; a D/R margin cannot identify the winner.866,191
2008 · U.S. Senate ↗R+24.51,210,690
2002 · U.S. Senate ↗Not a D–R contestThe ballot was not a Democrat versus a Republican; a D/R margin cannot identify the winner.776,850

Margins compare Democratic and Republican vote totals. Nonstandard ballots are labeled separately.

The money

Bar length compares reported receipts in this race; the tick marks cash on hand. A missing filing stays blank rather than becoming $0.

One more fundraising reportCall the Map · $0

The candidates are comfortably out-fundraising the website covering them. A little rude, perhaps, but statistically unsurprising.

Received so far
$0
Measured compute
$26,188.58

Ko-fi and Buy Me a Coffee receipts are counted through Sep 1, 2026. Measured compute prices model runs at standard published API rates; it is not what I paid. Hosting, data and subscriptions, the domain and my own time are not counted. Donations buy gratitude, never a forecast adjustment.

Ko-fi ↗Buy Me a Coffee ↗

See the public support ledger →

Outside spending

Support + opposition · separate from receipts

For and against Adam Hamilton$1.4M

1 spending group
GroupForAgainst
MAIN STREET FUND$0$1.4M

For and against Roger Marshall$1.1M

3 spending groups
GroupForAgainst
PEOPLE OVER POLITICS ACTION FUND$0$842K
SENATE CONSERVATIVES FUND$215K$0
SENATE CONSERVATIVES ACTION$46K$0

Includes primary spending. Opposition is recorded against its named target; no benefit to another candidate is assumed.

$2.2M in outside spending on earlier candidates.

FEC filings · through 07/15/2026 · Definitions & method

Race context

Forecast votes cast
979,150
Forecast turnout
46.0% of the voting-eligible population
2024 presidential margin
R+16.4

Statewide, 46.9% of the voting-eligible population is projected to cast a ballot; the lower figure above is the share projected to vote in this race.

Population profile Select a measure for its source and denominator

White alone · 79.8%2,341,473 of 2,935,922 · Residents2022 Census · matched race geography
Demographic source and limits

U.S. Census Bureau, 2022 American Community Survey 5-year estimates ↗

Coverage

1 story · 6 quotes

All coverage and full posts on the Wire →