Former Maine Senate President Troy Jackson has effectively secured the Democrat nomination to challenge Republican U.S. Sen. Susan Collins in November, winning support from a majority of delegates ahead of the state's convention next weekend, Politico reported on Sunday.
Democrats are scrambling to regroup after their initial nominee, Graham Platner, left the race following a sexual assault allegation.
Collins is widely seen as the most vulnerable incumbent Republican senator in 2026, making the Maine seat critical to Democrats' hopes of overturning Republicans' 53-47 Senate majority in the midterm elections.
Nearly two-thirds of the 601 delegates have committed to backing Jackson at the statewide convention, though they are not legally bound to do so, Politico reported. Jackson dominated county-level meetings over the weekend that selected the delegates, with two rivals falling far behind.
One of those rivals, Maine Secretary of State Shenna Bellows, withdrew earlier on Sunday, saying she would focus on her current role and urging Democrats to unify quickly to defeat Collins.
Jackson, a former logger from rural northern Maine, has deep roots in the state's labor movement and close ties to the party's progressive wing; Sen. Bernie Sanders, a Vermont Independent who caucuses with Democrats, endorsed him in a past gubernatorial race.
Jackson had campaigned for Platner during the primary but joined Democrats who urged him to step aside after the allegation emerged.
Platner, a populist progressive, suspended his campaign on July 8 after a woman accused him of sexually assaulting her while they were dating five years ago, ending a run marked by personal controversies. He denies the allegation but said pressure from state and national Democrats made it impossible to continue.
He had won the nomination in June with more than 70% of the primary vote after his main rival, Governor Janet Mills, suspended her campaign in April.
The state's Democratic Party has until July 27 to name a replacement.
Collins is the only Republican up for reelection in a state former Vice President Kamala Harris won in 2024, defeating President Donald Trump there by about 7 points. Even so, Collins has held her seat since 1997 and Democrats have not won a Senate race in Maine since 1988.