The closely matched Polymarket ranges for Massachusetts Senate turnout center on mid-2 million totals because the November 2026 general election features a low-competition race in a solidly Democratic state. Incumbent Ed Markey holds a wide polling lead over Republican John Deaton, while the Democratic primary between Markey and Seth Moulton has generated limited enthusiasm, as Massachusetts Secretary of the Commonwealth William Galvin recently noted. Traders are weighting typical midterm participation patterns, including modest early-voting and mail-ballot volumes, against historical drop-off from presidential-year levels in a state where registered voters number roughly 5 million. No major national or state-level catalysts have emerged to shift expectations materially. Greater-than-anticipated mail returns, heightened mobilization efforts, or late-cycle developments could widen separation among the leading bins, while continued low interest would reinforce clustering in the 2.5M–2.8M range.