Maine’s political landscape was jolted on October 14, 2025, as Governor Janet Mills, a Democrat and the state’s first female governor, announced her much-anticipated candidacy for the U.S. Senate. Her decision sets up a potentially historic contest against Republican incumbent Susan Collins, a formidable political figure who has held her Senate seat since 1997 and never lost an election for the chamber. But before Mills can take on Collins, she’ll first have to navigate a contentious Democratic primary, reflecting a broader national debate within her party about generational change and ideological direction.
Mills’s entrance into the race immediately changed the calculus for national Democrats. As Crystal Ball reported, the Maine Senate race was shifted from “Leans Republican” to “Toss-up” status, making it one of only four such races nationwide. This adjustment underscores Maine’s critical role in Democrats’ uphill battle to reclaim the Senate majority in 2026. If Democrats were to win all four Toss-up contests and defend their current seats, they’d still be two shy of a majority—underscoring the steep challenge ahead.
In her campaign announcement video, Mills didn’t mince words. She declared, “I won’t sit idly by while Maine people suffer and politicians like Susan Collins bend the knee as if this were normal. My life’s work has prepared me for this fight, and I’m ready to win. This election will be a simple choice: Is Maine going to bow down or stand up? I know my answer.” According to Newsweek, Mills’s campaign is framing the election as a battle for the soul of Maine, with a clear contrast between her vision and Collins’s record.
Mills, now 77, has pledged to serve only a single term if elected, which would make her the oldest freshman senator in U.S. history. Her age and experience are central to both her appeal and the criticism she faces. She’s a moderate Democrat, known for breaking with her party on issues like drug decriminalization and, at one point, earning an A+ rating from the NRA. Senate Minority Leader Chuck Schumer personally recruited her to run, signaling the national party’s belief in her electability and gravitas. Her campaign, however, must first overcome a brewing generational and ideological split within the Democratic Party.
The primary field includes Graham Platner, an oyster farmer, Marine veteran, and progressive candidate endorsed by Senator Bernie Sanders. Platner, roughly half Mills’s age, has made waves with his outspoken stances—supporting Medicare for All, criticizing U.S. policy toward Israel, and vowing, “I stand right in the fucking way of anyone who’s going to try to come after the freedoms of the LGBTQIA+ community.” As CN reports, Sanders himself has publicly lamented the party establishment’s push for Mills, arguing, “It’s disappointing that some Democratic leaders are urging Governor Mills to run. We need to focus on winning that seat & not waste millions on an unnecessary & divisive primary.” Platner has cast his campaign as an effort “to reshape the Democratic Party.”
The tension between establishment moderates and progressive insurgents isn’t unique to Maine, but it’s especially pronounced here. Mills’s moderate record, including her opposition to drug decriminalization and past NRA rating, stands in contrast to Platner’s left-wing platform. The primary, as CN and Newsweek both note, is shaping up to be a microcosm of the Democratic Party’s national soul-searching after a difficult 2024 election cycle in which the party lost the presidency and failed to retake the House.
Mills’s campaign has also sought to tie Collins to former President Donald Trump, highlighting Collins’s votes to confirm Supreme Court Justice Brett Kavanaugh—who played a role in overturning Roe v. Wade—and claiming that Collins is complicit as Trump “rips health care away from millions of Americans” and “gives corporate CEOs a massive tax cut.” Yet Collins’s record is more complicated than these attacks suggest. As CN details, Collins is openly pro-choice, voted against Trump’s so-called “big beautiful bill,” and was one of only three Republicans to confirm Justice Ketanji Brown Jackson. She also voted to convict Trump in his second impeachment trial and sided with President Biden 67% of the time in the 117th Congress. In 2020, Collins defied dire polling and won reelection by eight points, even as Biden carried Maine by nine points.
Collins’s unique political identity—as a moderate Republican in a reliably blue state—has made her an electoral outlier. According to Crystal Ball, she is the only Republican in the Senate representing a state that voted against Trump in every presidential contest since 2016. Her favorability ratings, however, are mixed. Polls conducted between May and July 2025 show her approval ranging from a low of 12% to a high of 49%, with disapproval ratings as high as 58%. While these numbers suggest vulnerability, Collins’s history of outperforming polls and her reputation for independence make her a challenging opponent.
Meanwhile, Mills’s campaign is not without its own risks. In her announcement video, she spotlighted a February 2025 confrontation with Trump over transgender athletes in sports, recounting how she told the former president, “See you in court,” after he threatened to withhold federal funds from states that didn’t comply with his executive order. Mills ultimately prevailed in court, but the issue could be a double-edged sword: a March 2025 University of New Hampshire poll found that nearly two-thirds of Mainers oppose allowing transgender girls on girls’ sports teams.
As the Democratic primary heats up, Mills is widely considered the frontrunner, especially after brewery owner Dan Kleban dropped out and endorsed her. Still, the party’s internal divisions could shape the race’s outcome—and, by extension, the national balance of power. If Mills or another Democrat emerges from the primary too far to the left, some strategists worry it could hurt the party’s chances in the general election. On the other hand, if Mills secures the nomination but fails to energize the party’s progressive base, turnout could suffer.
For now, the Maine Senate race stands as one of the most closely watched contests of the 2026 cycle. With both parties facing internal rifts and the broader electorate as unpredictable as ever, the outcome remains far from certain. As Crystal Ball observed, “There are reasonable rejoinders to our reasoning for making Maine’s Senate race a Toss-up. But we do think there is enough question about this race to make it a Toss-up, even as this is still a somewhat vexing race to assess.”
With the stakes for Senate control hanging in the balance, all eyes are on Maine—a state whose quirky politics and fiercely independent voters may once again defy national trends and expectations.
