Races · Senate · 2026 · Massachusetts
Senate · class II · open seat · provisional matchup
Democrat vs John Deaton
Likely matchup — the Democratic nominee isn't settled. Shown as a provisional party matchup, not confirmed nominees.
Info · primary pending
The Democratic nominee hasn't been chosen yet
2 Democratic candidates remain. See the democratic primary →
Primary September 1, 2026.
Where this race stands
VerifiedSafe D · model 99% D
Polling average rates this race Safe D (D+20.5, sourced from polls).
The poliagg-v34 ensemble forecasts D+25.8 with an 80% CI ranging from D+15.6 (10th pctile) to D+36.1 (90th pctile), giving D a 99% chance of winning.
Tipping-point probability: 4.5% of simulations see this race as decisive for chamber control.
Polling momentum is moving toward R at 3.9pp/wk over the 30d window — a real shift, not noise.
Uncertainty score: 52/100 (medium). Polls and forecasts agree at a moderate level.
CITATIONS · safe-d · low-tipping · trending-r · uncertainty-medium
How confident are we?0 = certain · 100 = max uncertain
Combined
52
Medium uncertainty
Main driver: wide forecast CI (20.5pp).
Forecast CI width68
20.5pp 80% interval
Forecast CI width
Contribution68 / 100
Measured20.5pp 80% interval
Each driver is scaled 0–100; higher pushes the combined uncertainty score up. Lower it with more recent, tightly-clustered polls and models that agree.
Inter-model disagreement17
3.5pp across models
Inter-model disagreement
Contribution17 / 100
Measured3.5pp across models
Each driver is scaled 0–100; higher pushes the combined uncertainty score up. Lower it with more recent, tightly-clustered polls and models that agree.
Pollster dispersion46
4.6pp cross-pollster spread
Pollster dispersion
Contribution46 / 100
Measured4.6pp cross-pollster spread
Each driver is scaled 0–100; higher pushes the combined uncertainty score up. Lower it with more recent, tightly-clustered polls and models that agree.
Polling sparsity0
8 polls in 60d · target ≥ 8
Polling sparsity
Contribution0 / 100
Measured8 polls in 60d · target ≥ 8
Each driver is scaled 0–100; higher pushes the combined uncertainty score up. Lower it with more recent, tightly-clustered polls and models that agree.
Forecast · poliagg-v34
Predicted final margin
D +25.8
80% CI: D +15.6 → D +36.1 · win prob 99%
R+45R+23TIEDD+23D+45
Quality · inputs
Data quality · medium
| Polls used | 20 |
| Days to election | 118 |
| Residual σ | 8.01pt |
| Generated | 7/7/2026 |
▼ Compare with other models3 models
qgbt-v1GBT (qgbt)
D +22.5
80% CI D +19.4 → D +30.6
CV MAE 8.51
bayes-v1Bayes / Kalman
D +22.4
80% CI D +20.5 → D +24.2
CV MAE 1.46
consensusMarket-implied
D +17.6
no interval
market-implied
Polling average
Weighted, plus each pollster's measured bias subtracted before averaging.
Prediction markets
Consensus · D 96¢3 platformsupdated 11h ago
DisagreementMarkets are 44 points more bullish on D than polling. Markets 96% · polls 52%.
Cross-platform price · history
External cross-checkExternal
Not part of our model or polling averageVoteHubaggregator ↗
4 polls · through Jun 23, 2026 · latest University of New Hampshire
Ed Markey
VoteHub52.5%
VoteHub
Polling average52.5%
Bars are scaled to a 60% ceiling — candidate shares don’t sum to 100% once undecided/other voters are set aside.
no matching candidate in our average
Seth Moulton
VoteHub52.0%
VoteHub
Polling average52.0%
Bars are scaled to a 60% ceiling — candidate shares don’t sum to 100% once undecided/other voters are set aside.
no matching candidate in our average
John Deaton
VoteHub30.0%
VoteHub
Polling average30.0%
Bars are scaled to a 60% ceiling — candidate shares don’t sum to 100% once undecided/other voters are set aside.
PoliAgg avg30.6%
PoliAgg avg
Polling average30.6%
Bars are scaled to a 60% ceiling — candidate shares don’t sum to 100% once undecided/other voters are set aside.
Δ 0.6 pt below our average
VoteHub's independent average across 4 polls (through Jun 23, 2026): Ed Markey 52.5%, Seth Moulton 52.0%.
Independent comparison only — not part of our forecast or polling average. VoteHub aggregates its own poll set; the two candidates shown are its top by average and may not match our field.
All polls · 20 results
strongpositiveinfocautionflag
| Date | Pollster · trust signals | n · pop | Lean | Bias · track | vs raters | D · R |
|---|---|---|---|---|---|---|
| Jun 29, 26 | Univ. of New Hampshire | 623 · LV | NEUTRAL | — | +1.4aligned | 50 · 34 |
| Jun 29, 26 | Univ. of New Hampshire | 623 · LV | NEUTRAL | — | +1.4aligned | 50 · 30 |
| Jun 22, 26 | University of New HampshireFor · University of New Hampshire | 623 · LV | NEUTRAL | R +0.912 tracked | +0.3aligned | 50 · 34 |
| Jun 22, 26 | University of New HampshireFor · University of New Hampshire | 623 · LV | NEUTRAL | R +0.912 tracked | +0.3aligned | 50 · 30 |
| Jun 15, 26 | Suffolk University+1For · The Boston Globe | 500 · RV | NEUTRAL | D +1.221 tracked | +0.8aligned | 55 · 30 |
| Jun 15, 26 | Suffolk University+1For · The Boston Globe | 500 · RV | NEUTRAL | D +1.221 tracked | +0.8aligned | 54 · 26 |
| Jun 11, 26 | Suffolk University+1For · The Boston Globe | 500 · LV | NEUTRAL | D +1.221 tracked | +0.8aligned | 55 · 30 |
| Jun 11, 26 | Suffolk University+1For · The Boston Globe | 500 · LV | NEUTRAL | D +1.221 tracked | +0.8aligned | 54 · 26 |
| Apr 22, 26 | Univ. of New Hampshire+1 | 606 · LV | NEUTRAL | — | +1.4aligned | 55 · 32 |
| Apr 22, 26 | Univ. of New Hampshire+1 | 606 · LV | NEUTRAL | — | +1.4aligned | 56 · 25 |
Endorsements · 1 total
Source · Wikipedia · 1 candidate with no endorsements yet1
Endorsements tracked
Democrat0 · 0%
John Deaton1 · 100%
Total1
Scraped from each candidate’s Wikipedia endorsement list.
RJohn Deaton1 endorser
Most notable · Massachusetts Republican Party
Organizations1
Organizations · 1
- Massachusetts Republican Party
DDemocrat0 endorsers
no endorsers yet
No endorsements found yet. Endorsements come from the candidate's Wikipedia article (when one exists) and update with the daily scrape.
Money raised · own committees
FEC Schedule E (independent expenditures) + candidate-committee totals · last filing 2026-06-17Ed MarkeyS4MA00028 ↗
Receipts
$3.8M
Disburse
$3.1M
Cash on hand
$2.5M
Debts
$0
Top industries
Lawyers / law firms$29.6K
Lawyers / law firms · $29.6K
- Keches Law Group · $15.3K
- Clifford Law Offices · $14.3K
Individuals $29.6K · PACs $0
Internet$12.2K
Internet · $12.2K
- Google · $12.2K
Individuals $12.2K · PACs $0
Top contributors
KECHES LAW GROUP$15.3K
CENTERVIEW PARTNERS$15.0K
CLIFFORD LAW OFFICES$14.3K
ANTHROPIC$14.0K
NEW ENGLAND DEVELOPMENT$14.0K
Seth MoultonS6MA00296 ↗
Receipts
$4.3M
Disburse
$2.8M
Cash on hand
$3.3M
Debts
$0
Top industries
Securities & investment$45.4K
Securities & investment · $45.4K
- Fidelity Investments · $30.9K
- Bain Capital · $14.4K
Individuals $45.4K · PACs $0
Education$30.1K
Education · $30.1K
- Harvard Business School · $16.5K
- Harvard University · $13.6K
Individuals $30.1K · PACs $0
Computers / electronics$14.4K
Computers / electronics · $14.4K
- Francisco Partners · $14.4K
Individuals $14.4K · PACs $0
Top contributors
FIDELITY INVESTMENTS$30.9K
LEIDOS$21.8K
ALLY FINANCIAL$20.0K
HARVARD BUSINESS SCHOOL$16.5K
CHARLESBANK CAPITAL PARTNERS$14.6K
John Deaton
Receipts
$1.4M
Disburse
$571.6K
Cash on hand
$828.6K
Debts
$1.0M
Top industries
No industry data.
Top contributors
RIPPLE$10.6K
DIGITAL ASCENSION GROUP$7.2K
BOX COUNSEL$7.0K
CARRUTH$7.0K
SKYBRIDGE CAPITAL$7.0K
Outside spending · independent expenditures
FEC Schedule E (independent expenditures) + candidate-committee totals · 24/48-hr IE reportsIE total
$1.5M
D side
$90 · 0%
R side
$1.5M · 100%
Top spender
ADVANCE PROGRESS
| Spender | Side | Amount | Share | Target |
|---|---|---|---|---|
| ADVANCE PROGRESS other · boosts R
| R | $1.5M | 100% | against Ed Markey |
| COMMONWEALTH TOGETHER PAC super pac · boosts R
| R | $630.0K | 42% | against Seth Moulton |
| GIVEGREEN UNITED ACTION super pac · boosts D
| D | $80 | 0% | for Ed Markey |
| SIERRA CLUB INDEPENDENT ACTION super pac · boosts D
| D | $10 | 0% | for Ed Markey |
Editorial ratings · 5 raters
Cook · Sabato · Inside Elections · 538 · DDHQ et al.Safe D5
Safe D · 5 raters
- The Cook Political Report · Apr 12
- The Economist · May 21
- Inside Elections · Apr 22
- RealClearPolitics · May 18
- Sabato's Crystal Ball · Mar 3
The Cook Political Report
Safe DThe Economist
Safe DInside Elections
Safe DRealClearPolitics
Safe DSabato's Crystal Ball
Safe DDemographic crosstabs
age · education · race · genderNo demographic crosstabs published for this race yet. Most pollsters release only topline numbers; subgroup breakdowns (age, education, race, gender) appear here when a pollster publishes them.
In the news
32 shown · last 30d · Google NewsNews volume · 30d
32 articles · building history
News volume · last 30d
Articles32
Trendbuilding history
Article counts indexed by Google News; the sparkline traces weekly volume across the window.
Net favorability
+0.16
Coverage lean (D−R) · shift −0.23 wk
Net favorability
Score+0.16
Week-over-weekshift −0.23 wk
Tone of coverage, D minus R, scored from −1 (all R-favorable) to +1 (all D-favorable). 0 is balanced.
Coverage tilt
D 19%
Neutral 78%
R 3%
22% of outlets rated · by editorial lean
Coverage tilt · by outlet lean
D-leaning outlets19%
Neutral78%
R-leaning outlets3%
22% of outlets classified by editorial lean
G
Climate programs regain footing as Massachusetts Dems debate energy affordability
S
E&E News: Climate programs regain footing as Massachusetts Dems debate energy affordability
S
UNH Poll: Markey’s Lead Over Moulton Narrows Ahead of September Democratic Primary
M
Markey and Moulton will have first US Senate primary debate in WMass
Y
Markey and Moulton will have first senate debate in Western Massachusetts
W
Massachusetts Senate primary debate: Markey vs Moulton
N
Massachusetts Sen. Markey Blasts Trump’s “Big Beautiful Bill” as “Big Ugly Bill” on Anniversary
W
Massachusetts Senate primary debate: Markey vs Moulton
A
Markey-Moulton Mass. primary race remains tight
A
Markey-Moulton Mass. primary race remains tight
Page 1 of 4
Rating timeline
Verification trail
Polls verified20 / 20deterministic
Polls flagged—none
Markets ingested3 platformsupdated 11h ago
FEC filingssyncedcommittee + IE · 2026-06-17
Endorsements91 totalWikipedia scrape
News coverage32 / 30dGoogle News
Method · bounds + percentage totals + date-order checks