Ed Markey, facing Seth Moulton, has tapped into progressive energy in Massachusetts.
The Data Dive with Steve Kornacki
The Data Dive with Steve Kornacki

TUE., SEP. 1, 2026

Steve Kornacki

By Steve Kornacki

Welcome to The Data Dive, your subscriber-exclusive newsletter about the most consequential elections of the midterms. Every Tuesday morning, I’ll focus on the numbers, trends and data shaping the biggest stories heading into Election Day. I’ll also dig into the 2026 battlegrounds that will determine control of Congress — one district, one county, one city and maybe even one precinct at a time. Today, I’m previewing a Senate primary in Massachusetts that’s much more than a generational battle. Let’s dive in.

What I’m watching

Sen. Ed Markey is an 80-year-old political lifer seeking re-election at a time of deep frustration among Democratic voters with their party’s aging leadership class. But it will be a major upset if he’s defeated in today’s Democratic primary in Massachusetts.

Polls have shown the senator steadily building an advantage over his challenger, Rep. Seth Moulton, as the campaign has progressed. Emerson College’s final survey over the weekend pegged Markey’s advantage at 30 percentage points.

Not everyone expected it would end up this way. After all, Markey was first elected to the Massachusetts Legislature 54 years ago. He has been in Congress since 1976, spending nearly four decades in the House before moving up to the Senate in 2013. And Moulton, 47, believed he could channel Democrats’ antipathy toward the party’s old guard into a winning campaign against Markey.

(Andrew Harnik, Getty Images; Aaron Schwartz, SIPA USA via Reuters)

Why, seemingly, has he been unable to make his case?

 

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