Moulton Goes on TV. The Market Hasn't Moved.
Markey leads Moulton by 6 in the latest UNH poll, but the market holds at 72¢. Moulton’s first TV buy is running and 23% of primary voters are undecided.
Ed Markey sits at 72¢ on our cross-platform consensus — Kalshi, Polymarket, and PredictIt all pricing the incumbent senator as a clear favorite ahead of the Sept. 1 Massachusetts Democratic primary. Seth Moulton, who launched his campaign in October on an explicit generational-change argument, sits at 25¢.
The latest polling puts the gap at 6 points.
A University of New Hampshire Survey Center poll conducted June 18–23 — the most recent publicly available survey of the race — found Markey leading Moulton 41 to 35 percent among likely Democratic primary voters, according to MassLive. That's down from a 13-point Markey advantage in the same pollster's April survey, and from a 17-point lead in a Boston Globe/Suffolk University poll also conducted in April.
Twenty-three percent of likely primary voters remain undecided — a bloc larger than the current polling gap.
And now Moulton is on television for the first time.
The TV Buy Question
The UNH survey was conducted before Moulton's campaign launched its first TV ads. Moulton's campaign noted that detail prominently: the gap closed from 13 points to 6 on earned media and grassroots organizing alone — the TV buy has not yet been reflected in any public polling.
That's the bullish case for Moulton: if ads can shift the race by another 6 points before Sept. 1, he enters toss-up territory. The market is not pricing that scenario. At 72¢, bettors are treating incumbency, endorsements, and institutional infrastructure as a durable edge.
Markey, who has served in Congress since 1977 and has been in the Senate since 2012, has accumulated endorsements from elected officials across the commonwealth. He dominates the UNH poll among self-identified liberals (51%) and progressives (52%), who tend to set the terms of Democratic primaries in Massachusetts, according to MassLive's reporting on the UNH data.
Where Moulton Lives
Moulton's coalition in the UNH survey is concentrated among moderates — he took 70 percent support among self-identified moderate primary voters, per Axios Boston. He also performs better among unenrolled voters who pull Democratic ballots.
The structural challenge is that Democratic primaries in Massachusetts run heavily on self-identified liberals and progressives. Moulton's moderate coalition exists — but it may not be the path to a primary win unless a large share of the undecided bloc breaks his way.
That undecided question is the key variable. Twenty-three percent undecided with 35 days to go is an unusually large pool for an incumbent primary race. Moulton's campaign argues those voters are looking for change and represent his ceiling; Markey's argument is that incumbents hold undecideds at a higher rate than challengers.
The Last Debate
The final major inflection point before the primary is a debate scheduled for Aug. 20, hosted by WBUR, WGBH, and the Boston Globe. That's 11 days before the Sept. 1 vote — Moulton's last earned-media opportunity to consolidate undecideds and test whether the TV buy has moved the underlying numbers.
If new polling before the debate shows Moulton within 3 points, the market at 72¢ will look stale. If Markey's lead has held steady at 6 or wider, it will look accurate.
The volume — $279,500 across all three platforms — is thin relative to other Senate races this cycle. That thin liquidity means the market could reprice quickly if a post-TV-buy poll shows meaningful movement. Watch for August surveys.
Sources: Markey/Moulton primary odds: electionpredictions.us cross-platform consensus (Kalshi, Polymarket, PredictIt), July 28, 2026. UNH Survey Center poll (conducted June 18–23): MassLive, July 1, 2026 (https://www.masslive.com/politics/2026/07/moulton-closes-in-on-markey-in-new-mass-senate-poll.html); Axios Boston, July 1, 2026. Moulton campaign TV buy and press release: sethmoulton.com, July 26, 2026. Poll ideological breakdown (liberals/moderates/undecided): MassLive, July 1, 2026. Markey congressional service: official Senate biography. Aug. 20 debate: WBUR/WGBH/Boston Globe.