Twitch streamer and left-wing activist Hasan Piker celebrated after Senator Ed Markey, 80, defeated Representative Seth Moulton in the Massachusetts Democratic Senate primary, framing the result as a win for progressive politics over generational change. Moulton, 33 years Markey's junior, had campaigned on the need for fresh leadership, but Markey positioned himself as the more authentically progressive candidate, emphasising his support for transgender rights in sport and aggressive climate action, positions Moulton had argued cost Democrats support in 2024.

Markey received endorsements and praise from prominent figures on the left, including the Sunrise Movement, veteran strategist David Axelrod and Senator Bernie Sanders, with Axelrod noting that Markey, first elected 50 years ago as a social conservative, had reinvented himself around causes such as the Green New Deal and Medicare for All. Having won the primary, Markey advances to the general election on 3 November, where he is heavily favoured in the strongly Democratic state; he most recently won re-election over a Republican challenger by a margin of 66.2% to 33.0%.