Massachusetts Senator Ed Markey has fended off a primary challenge from Rep. Seth Moulton to secure the Democratic nomination for a third full Senate term, with the Associated Press calling the race less than an hour after polls closed on Tuesday. The 80-year-old Markey won by embracing his progressive credentials, notably by continuing to voice support for transgender athletes in sports, a stance most Democrats have avoided this election cycle. The result is a significant test of whether the party's progressive wing can still prevail over calls for generational change, particularly following the turmoil around Joe Biden's age during his 2024 re-election bid.

Moulton, who campaigned on renewing the party's leadership and cited concerns about "male or formerly male" athletes competing against girls, argued the trans sports issue had cost Democrats support in the 2024 elections. Markey countered by insisting his position reflected Massachusetts values, and secured backing from prominent progressives including Senator Bernie Sanders and Representative Alexandria Ocasio-Cortez. Given the state's strongly Democratic lean, having not elected a Republican senator since 2013, Markey's primary win is expected to translate into victory in November. It is also his second successful defence against a younger rival, having previously defeated Joe Kennedy III in 2020, even as other veteran Democrats, such as Connecticut's John Larson, have lost to younger challengers this cycle.