A heated and expensive Democratic primary in Maine is shaping up to determine who will face Republican Sen. Susan Collins in November. With the June 9 primary approaching, two candidates — Gov. Janet Mills and political newcomer Graham Platner — have been locked in a high-profile, often negative contest as outside Republican groups pump millions into protecting Collins’ seat.
The contenders
Mills, a two-term governor, entered the race after encouragement from Senate Minority Leader Chuck Schumer and is viewed by many party leaders as the safer general-election nominee because of her statewide record. Platner, an Iraq and Afghanistan veteran who now farms oysters and launched his campaign before Mills entered, has run as an insurgent, winning Sen. Bernie Sanders’ endorsement and drawing energized crowds with a retail, anti-establishment approach.
Controversies and polls
Platner’s insurgent energy has been complicated by the resurfacing of offensive, now-deleted social media posts and a previously covered tattoo with imagery some saw as troubling. He acknowledged the posts, apologized publicly, and has attributed his earlier online conduct to anger and struggles after military service. Mills has highlighted those old posts in campaign ads aimed at female voters; Platner has responded with apologies, events featuring women who defended him, and his own ads pushing back.
Recent polls from the University of New Hampshire Survey Center and Maine-based Pan Atlantic SMS have shown Platner ahead of Mills in the primary, even as the two continue to trade attacks and boost ad buys.
Money and outside influence
Spending in the Democratic primary has been intense. AdImpact reports that Platner has spent about $4.2 million on advertising versus roughly $1.16 million for Mills, and his campaign outraised her nearly three-to-one in FEC filings through last year. Collins herself has spent comparatively little directly — about $240,000 — but outside Republican groups have spent heavily to defend her. One Nation, an issue-advocacy group, has spent just over $10 million on ads, mailers, texts and web placements highlighting Collins’ work securing federal funding for Maine. Because One Nation is structured as issue advocacy, it can run favorable messages without direct coordination or campaign-style donor disclosures.
Democratic-aligned super PACs and dark-money entities are active as well, though much of that spending has targeted Collins rather than explicitly backing one primary contender. Still, the Mills–Platner rivalry has drawn the bulk of attention and resources on the Democratic side.
Strategic calculations and risks
Analysts say the heavy early spending is logical: Platner needs statewide name recognition, while Mills aims to define him to primary voters and weaken his appeal among constituencies she hopes to hold. Mills’ attacks have deliberately emphasized Platner’s past comments to mobilize women voters, a bloc she sees as pivotal. Observers warn, however, that aggressive intra-party attacks risk alienating Platner’s supporters, suppressing turnout or deepening divisions ahead of the general election against Collins.
The outlook
The primary remains competitive and costly, and how it unfolds will shape the November match-up. Beyond deciding who challenges Collins, the outcome may also determine whether Maine Democrats emerge united and energized for the general election or fractured after a bruising fight.