2026 midterm forecast
Massachusetts Senate
Ed Markey (D) vs. John Deaton (R)
Forecast published October 30, 2026 · Election Day is November 3, 2026
Foresight forecast
Chance to win
>99%
Ed Markey
Projected margin
D+32.4
±11 points, 95% range
Undecided
15%
of likely voters
Two-party vote
Key insights
Deaton faces long odds against Markey in the Massachusetts Senate race
Markey holds the seat for Democrats and is in little danger of losing it to Republican Deaton. His smallest lead in any type of community is 16.8 points, in rural areas.
Women give Markey a 41.1-point edge, and men a smaller 23.5. Crossover is rare. Harris voters back Markey at 96%, and Trump voters back Deaton at the same rate.
The race
- Democrat
- Ed Markey (D)
- Republican
- John Deaton (R)
- Seat held by
- Ed Markey (D), running
Democratic Sen. Ed Markey, who defeated U.S. Rep. Seth Moulton in the Sept. 1 primary, faces Republican John Deaton, an attorney and the 2024 nominee, as he seeks a third full term. Markey says he would check President Trump, and he backs Medicare for All. Deaton calls himself an independent-minded Republican and supports nuclear power and natural gas.
Campaign summary as of October 29, 2026.
Vote by group
Own vote of likely voters in each group, two-party margin.MarkeyDeaton
Age
Gender
Education
Area
By county
Foresight's margin in each county.
County margins in points. Faded: fewer than 5 respondents. Blank: no respondents.
How this forecast is made: read the method.