Incumbent Ed Markey’s strong backing from progressive voters, organized labor, and established Democratic figures like Elizabeth Warren has anchored his lead in the Massachusetts Democratic Senate primary, set for September 1, 2026. Recent Emerson College polling from early May shows the race tightening to 37 percent for Markey versus 32 percent for challenger Seth Moulton, with 29 percent undecided after wider margins earlier in the cycle. Moulton’s push for generational change and stronger performance among unenrolled voters has narrowed the gap, yet Markey’s decades of name recognition and fundraising edge sustain the current trader consensus reflected in the 71 percent probability. Minor candidates Ayanna Pressley and Alexander Rikleen remain marginal factors given limited support.