Platner wins Maine Senate primary to challenge Susan Collins

Graham Platner’s victory in Maine’s Democratic Senate primary put a combat veteran and oyster farmer on a collision course with Susan Collins, one of the most resilient incumbents in Washington. The November race will help answer a central question in Democratic strategy: whether Collins can be beaten by nationalizing the contest around Washington politics, or whether Platner’s coastal Maine biography can localize the race enough to erode her cross-party appeal.

Platner clinched the nomination on June 9 and will challenge Collins, who is seeking a sixth term after first winning the seat in 1996 and taking office in January 1997. Collins has built her career on longevity and bipartisan dealmaking, and her path has been unusually durable in a state that often rewards independence. In 2020, she became the first-ever Republican woman to win a fifth Senate term.

For Democrats, the stakes are obvious. The Maine seat is widely seen as one of the contests that could determine control of the U.S. Senate in the 2026 midterms, and Platner’s profile is meant to broaden the map in a race where Collins has long benefited from a reputation that cuts across party lines. Platner entered the general election after Gov. Janet Mills suspended her Senate campaign in April, leaving him as the dominant Democratic candidate heading into Election Day.

His campaign was also shaken by damaging allegations about his personal history, which drew scrutiny from Republicans and some Democrats alike. Collins publicly called those allegations “troubling” before the primary, while Platner stayed defiant and leaned into an anti-establishment message aimed at working-class voters. That contrast now sits at the center of the general election: whether Collins can hold her coalition together against a challenger trying to turn biography into political leverage.

Maine’s ranked-choice voting system adds another layer to the race. The state uses ranked-choice voting in its federal and statewide primaries, a method that can matter if no candidate clears a majority on the first round and a winner has to emerge through subsequent rankings. The general election will unfold after a June 9 primary day that also featured contests in South Carolina, Nevada and North Dakota, making Maine part of a broader night of races with national implications.

Platner’s nomination did more than settle a primary. It set up a test of whether Democrats can finally make Collins look less like a safe exception and more like a vulnerable incumbent.