Polls closed at 8 p.m. Tuesday across the 39 cities and towns of Massachusetts’ 6th Congressional District, ending a Democratic primary that will decide who succeeds U.S. Rep. Seth Moulton in a seat voters have not filled without an incumbent on the ballot since 1978.
Six Democrats appeared on the ballot: state Rep. Tram Nguyen of Andover; Dan Koh, also of Andover; John Beccia of Lynnfield; Jamie Belsito of Topsfield; Beth Andres-Beck of Middleton; and Mariah Lancaster of Salem, who ended their campaign three days before the primary and endorsed Nguyen but remained on the ballot. The winner advances to face Republican Micah Jones of Essex on Nov. 3 in a district the Cook Political Report rates 11 points more Democratic than the nation.
Why the seat is open
The seat opened when Moulton, a Salem Democrat who has held it since January 2015, decided not to seek reelection and instead ran in Tuesday’s Democratic primary for U.S. Senate, challenging 80-year-old Sen. Edward Markey on a message of generational change. Moulton, a Marine Corps veteran who served four tours in Iraq, won the 6th District seat in 2014 by defeating nine-term incumbent U.S. Rep. John Tierney in the primary — the first sitting Massachusetts congressman to lose a primary since 1992 — then beat Republican Richard Tisei that November.=
Nguyen, an Andover state representative and former Greater Boston Legal Services attorney, came to the United States from Vietnam as a 5-year-old refugee and campaigned on a legislative record that includes a coercive-control law she co-wrote with state Rep. Natalie Higgins, signed by Gov. Maura Healey in 2024. Koh, also of Andover, is a former chief of staff to Boston Mayor Marty Walsh and a Biden White House aide who lost a 2018 congressional primary to now-U.S. Rep. Lori Trahan by 145 votes. Beccia, of Lynnfield, is a financial-technology executive who loaned his own campaign roughly $3 million. Belsito, of Topsfield, is a former state representative who ran on a “People’s Pledge” rejecting corporate PAC, super PAC and AIPAC money. Andres-Beck, of Middleton, is a software engineer running as a Democratic Socialist…