COYNTOSSby @achasecoyne

Updated September 29, 2026 · model inputs through September 27, 2026

Massachusetts Senate Forecast

‹ See all Senate races

Senator Ed Markey, a fixture of Massachusetts politics for decades, faces Republican John Deaton, a trial lawyer and political newcomer. Massachusetts is among the country’s bluest states, but Markey’s path still runs through a Democratic primary before the general election.

Forecast summary

Model margin
D+31.67
Rating
Safe D
Polling average
D+24.36
Fundamentals
D+36.96
Matchup
Ed Markey vs. John Deaton

FORECAST HISTORY

Model margin over time

Forecast history will appear after the first recorded model release.

No candidate win probabilities have been published from a frozen, label-verified simulation run yet.

MODEL BREAKDOWN

How the forecast is built

The polling average and fundamentals are blended at their published weights.

Polling average — — · —
Fundamentals — — · —
Projected margin — Published model output
Polling Fundamentals

Margins are D-minus-R points. Candidate strength is included in fundamentals; its separate score is not published. Values are rounded to two decimals.

POLLING INPUTS

Polls behind the average

Polling average
D+24.36

Field dates Pollster Sample Results
Fielded Aug 20–Aug 24, 2026UNH881 LVD Ed Markey 49% · R John Deaton 30% · O Joe Tache 7%
Fielded Aug 5–Aug 12, 2026UMass Amherst445 LVD Ed Markey 51% · R John Deaton 30%
Fielded Jun 18–Jun 23, 2026UNH633 LVD Ed Markey 50% · R John Deaton 34%
Fielded May 26–May 29, 2026Boston Globe/Suffolk500 LVD Ed Markey 55% · R John Deaton 30%

The published average comes directly from the workbook. Polls are not equally weighted, and the browser does not recompute the forecast.

The published average comes directly from the workbook. Polls are not equally weighted, and the browser does not recompute the forecast.

See all Senate races