Massachusetts — U.S. Senate
Currently held by a Democrat · incumbent running
Democrat
Ed Markey
99.8%
Republican
John Deaton
0.2%
ForecastSafe D
- Projected margin
- D+27.5
- 80% range
- D+16.7 to D+38.4
- Partisan lean
- D+28.3
- Uncertainty multiplier
- 1.65×
The 80% range comes from 200,000 simulations in which this race’s error is correlated with every other race through the national, state and demographic layers.
How the estimate is built
74%27%
Polls 74%Fundamentals 27%
- Polling average
- D+25.6
- Fundamentals
- D+43.7
- Blended
- D+27.7
- Similar-race shift
- −2.4
- Poll–fundamentals gap
- 18.1 pts
PollingDR matchup
- Polls in window
- 8
- Distinct pollsters
- 4
- Most recent
- September 22, 2026
- Democrat
- 52.8%
- Republican
- 27.2%
- Undecided / other
- 14.6%
- Spread between polls
- 2.3 pts
Fundamentals
- Partisan lean
- D+28.3
- Elasticity
- 1.10
- Incumbency
- +4.2
- Candidate experience
- 0.0
- Fundraising
- +3.5
- National environment
- D+7.1
- Expected margin
- D+46.0
The polls behind this number10 most recent of 8 in the window
| Pollster | Dates | Sample | D | R | Margin |
|---|---|---|---|---|---|
| MassINC Polling Group | September 22, 2026 | 800 LV | 52 | 26 | D+26 |
| University of New Hampshire | September 21, 2026 | 564 LV | 53 | 30 | D+23 |
| University of New Hampshire | August 24, 2026 | 881 LV | 49 | 30 | D+19 |
| University of Massachusetts Department of Political Science/YouGov | August 12, 2026 | 800 RV | 51 | 30 | D+21 |
| University of New Hampshire | June 23, 2026 | 623 LV | 50 | 34 | D+16 |
| Suffolk University | June 12, 2026 | 500 RV | 55 | 30 | D+25 |
| University of New Hampshire | April 20, 2026 | 603 LV | 55 | 32 | D+23 |
| University of New Hampshire | February 16, 2026 | 616 LV | 56 | 27 | D+29 |
| Suffolk University | November 23, 2025 | 500 RV | 54 | 31 | D+23 |
| SurveyUSA | March 4, 2025 | 775 RV | 45 | 26 | D+19 |
Each poll is weighted by recency, the square root of its sample size and its pollster rating, then adjusted for that firm’s house effect, its sampled population and any partisan sponsorship — so the average above is not the mean of this column.
Campaign fundraisingFEC filings to Invalid Date
| Candidate | Party | Raised | Cash on hand |
|---|---|---|---|
| Seth Moulton | DEM | $6.2M | $1.8M |
| John Deaton | REP | $1.6M | $712k |
Receipts across the cycle, from FEC bulk filings. The model uses the ratio between the two sides rather than either total, and weights it lightly — money follows a competitive race at least as much as it causes one.