Massachusetts Senate 2026 Dem Primary
The Massachusetts Senate dem primary is scheduled for September 1, 2026. The model sees a close race: Ed Markey edges Seth Moulton, 54% to 45% in a 3-candidate field. Ed Markey is the incumbent, leads the field in reported fundraising, and has the most tracked endorsements. Public polling is available for this race and feeds the forecast alongside fundraising, endorsements, and historical results.
Current win probabilities
- Ed Markey (incumbent) — 54%
- Seth Moulton — 45%
- William F. Gates Jr. — 2%
Probabilities update daily from polls, fundraising, endorsements, and historical results. Last updated September 11, 2026.