Why It Matters
The Democratic primary for Maine’s U.S. Senate seat has effectively ended, setting up a November showdown between incumbent Republican Sen. Susan Collins and oyster farmer Graham Platner. The race is considered crucial for Democrats hoping to reclaim the Senate majority, though Platner faces scrutiny over past controversial social media posts.
What Happened
Maine Gov. Janet Mills announced Thursday she is suspending her Democratic primary campaign for U.S. Senate, citing insufficient financial resources to continue. Mills, 78, had entered the race later than Platner and struggled to match his fundraising pace.
In a statement, Mills said she possesses the drive, commitment, and experience needed for the race but lacks the financial backing required in modern political campaigns. She called the decision incredibly difficult after decades of public service in Maine.
The move clears the path for Platner, 41, to become the Democratic nominee challenging Collins in November. Collins is seeking her sixth term in the Senate, representing a state that President Donald Trump has lost three times.
By the Numbers
Platner raised $4.1 million in the first quarter of 2026, compared to Mills’ $2.7 million. A February University of New Hampshire poll showed Platner leading Mills 64% to 26% among likely Democratic primary voters. Collins is 73 years old, while Mills would have been the oldest freshman senator ever elected at 78. The Maine primary is scheduled for June 9.
Zoom Out
Senate Minority Leader Chuck Schumer, who recruited Mills into the race, quickly pivoted to support Platner alongside Sen. Kirsten Gillibrand, head of the Democratic Senatorial Campaign Committee. The two Democrats issued a joint statement arguing Collins has never been more vulnerable after years of allowing what they characterized as Trump’s abuses of power.
Republicans expressed confidence in Collins’ chances against Platner. Sen. Tim Scott of South Carolina, head of the National Republican Senatorial Committee, called Platner too extreme for Maine. A pro-Collins super PAC launched a $2 million ad campaign against Platner last week, signaling Republicans view him as the likely nominee.
Platner has secured endorsements from progressive senators including Bernie Sanders of Vermont, Elizabeth Warren of Massachusetts, Ruben Gallego of Arizona, and Martin Heinrich of New Mexico. His campaign positioned itself to the left of Mills and promised more aggressive opposition to the Trump administration.
What’s Next
The general election will likely focus on Collins’ record chairing the Senate Appropriations Committee and whether she has adequately stood up to Trump while delivering for Maine. Collins voted against Trump’s priority agenda bill last year, one of three Senate Republicans to do so.
Republicans plan to highlight Platner’s past social media activity, including deleted posts where he criticized police and made disparaging comments about rural white Americans. Platner has disavowed those posts and faced questions about a chest tattoo resembling a Nazi symbol, which he said he regretted and had covered. He maintains the past statements do not reflect who he is today.
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