Dan Koh maintains a commanding position in the Massachusetts 6th Congressional District Democratic primary due to his substantial fundraising lead of roughly $4.7 million, extensive television and mail advertising, and endorsements from former President Biden, Vice President Harris, unions, and local officials. His prior White House experience and name recognition from an earlier congressional bid have translated into consistent polling leads of double digits ahead of the September 1 vote. State Representative Tram Nguyen trails as the leading alternative, drawing on legislative experience and grassroots appeals, though with far less cash on hand. Other candidates remain marginalized by limited resources and visibility. Scenarios that could still alter the outcome include unusually low turnout or last-minute shifts in undecided voters, though the resource gap and recent polling trends have narrowed such possibilities.