Daniel Koh, a former Biden administration official, has secured the Democratic nomination for the U.S. House seat in Massachusetts' 6th Congressional District, according to projections from Decision Desk HQ. Koh defeated progressive state Representative Tram Nguyen in a closely watched primary battle, positioning himself as the heavy favorite to succeed outgoing Representative Seth Moulton in the general election.
With 68 percent of precincts reporting Tuesday evening, Koh led Nguyen by a margin of roughly 41 percent to 30 percent, a decisive gap that underscored his broad appeal among district voters. Four other candidates appeared on the ballot, including veterinarian Mariah Lancaster, who suspended her campaign over the weekend and threw her support behind Nguyen.
The open seat attracted significant attention as Moulton, who has represented the district for a decade, chose to challenge incumbent Senator Ed Markey in the Democratic primary. Moulton's decision set off a competitive race to fill his seat, with Koh and Nguyen representing different wings of the party.
Koh, who served as a White House official under President Biden and previously as chief of staff to Boston Mayor Marty Walsh, garnered a series of high-profile endorsements, including from former President Biden, former Vice President Kamala Harris, and former Transportation Secretary Pete Buttigieg. His campaign emphasized his experience in government and his ability to deliver for the district.
Nguyen, a state representative known for her progressive advocacy, received backing from Massachusetts Democratic Representatives Lori Trahan and Ayanna Pressley, as well as The Boston Globe. Her campaign focused on grassroots organizing and progressive policy priorities, but ultimately fell short in a district that has historically favored moderate Democratic candidates.
The 6th District, which covers the northeastern part of the state, is considered safely Democratic, making Koh the overwhelming favorite in the November general election. He will face Republican Micah Jones, a lawyer and Army veteran who ran unopposed for the GOP nomination.
Koh's victory marks a return to political campaigning after his 2018 bid in Massachusetts' 3rd District, where he lost to Trahan. He later served as Walsh's chief of staff in Washington before joining the White House's Office of Intergovernmental Affairs, giving him a deep well of experience in both local and federal governance.
The primary results come amid broader generational pushes within the Massachusetts Democratic Party, as younger and more progressive candidates challenge established figures. While Koh's win represents a victory for the party's establishment wing, the race highlighted the ongoing ideological tensions that are likely to shape future contests.
With the primary behind him, Koh now turns his attention to the general election, where he is expected to campaign on his record of public service and his ability to work across levels of government. The seat's Democratic leanings suggest that Koh's path to Congress is clear, barring an unexpected turn in the campaign.
