MA · Senate 2026 · Updated Aug 27, 2026, 2:03 a.m. ET

Massachusetts

Rated Solid D

Ed Markey wins this seat in >99 in 100 simulations. Call it all but certain.

Ed MarkeyDIncumbent>99 in 100
John DeatonR<1 in 100

Over time

How the forecast has moved

Chance in 100 the seat goes to each side: blue for the Democratic caucus, red for the Republicans · one point per day · hover or tap to read the lines

The margin

How close it lands

Each simulation produces a final margin. The curve shows where those margins fall; the tinted areas on either side of even are the futures each party wins.

← John Deaton aheadEd Markey ahead →

Where the simulated margins land · marker at the average margin

Under the hood

What's driving the number

The forecast blends a weighted poll average with a fundamentals model: the state's partisan lean, incumbency, the national environment, and fundraising. Positive points favor the Democratic side of the margin; negative favor the Republican side.

Partisan leanD +27.3
IncumbencyD +2.5
National environmentD +5.1
FundraisingD +1.1

Fundamentals sayD +35.9
The polls sayD +25.0
Blended forecast marginD +31.7

The blend puts 39 percent of its weight on the polls and 61 percent on the fundamentals; polls take over as more arrive and election day nears.

The markets

What the betting markets say

Prediction markets put a price on this seat too: what people are paying for a contract that pays out if Ed Markey wins, read as an implied probability. Shown for comparison only. This is not betting advice, and market prices never feed the model.

Ed Markey winsThis forecast>99 in 100
Ed Markey winsKalshi97 in 100
Ed Markey winsPolymarket98 in 100

Market prices as of Aug 27, 2026, 2:03 a.m. ET

The evidence

The polls, as the model sees them

Every public poll of this race, with the weight the model gave it in the latest run. Weights reward recency, sample size, and pollster track record; the house adjustment corrects each pollster's habitual lean before averaging.

Poll	Dates	Sample	D–R	Margin	House adj.	Weight
University of New Hampshire	Aug 20–24	881 LV	49–30	D +19.0	−1.1	74%
UMass Amherst / YouGov	Aug 5–12	800 RV	51–30	D +21.0	+0.1	25%
University of New Hampshire	Jun 18–23	623 LV	50–34	D +16.0	−1.1	<1%
Suffolk University	Jun 8–12	500 LV	55–30	D +25.0	+1.2	<1%
University of New Hampshire	Apr 16–20	603 LV	55–32	D +23.0	−1.1	<1%
University of New Hampshire	Feb 12–16	620 LV	56–27	D +29.0	−1.1	<1%
Cygnal (R)	Jan 22–25	800 LV	54–30	D +24.0	+1.2	<1%
Suffolk University	Nov 19–23	500 RV	54–31	D +23.0	+1.2	0%
SurveyUSA	Feb 28–Mar 4	775 RV	45–26	D +19.0	+1.8	0%

How the weights, the blend, and the simulation work is spelled out on the methodology page.