Maine Governor Janet Mills enters Senate race, tees up intraparty battle

AUGUSTA, Maine (CN) — Maine’s Democratic governor, Janet Mills, announced Tuesday that she’s running for the U.S. Senate against long-serving Republican Susan Collins, a move that shakes up the race in a state the Democratic Party almost certainly needs to win if it hopes to flip the Senate in the midterms next year.

But before Mills can take on Collins, she will first have to win a primary that’s a microcosm of the larger split in her party between an older generation of moderates and younger, more left-wing progressives.

Mills is 77 and would be 85 at the end of her Senate term, roughly the same age that Joe Biden would have been at the end of his presidency if he had been reelected. If she wins, she will be the oldest freshman senator in U.S. history. She has pledged to serve only one term.

Mills is a moderate who has often broken with the Democratic-controlled state legislature; she opposes the decriminalization of drugs and once received an A+ rating from the NRA. Senate Minority Leader Chuck Schumer recruited her to run.

She will be opposed in the primary by Graham Platner, an oyster farmer and Marine veteran roughly half her age who has been endorsed by Senator Bernie Sanders. Platner supports Medicare for All, has been harshly critical of Israel and stated, “I stand right in the fucking way of anyone who’s going to try to come after the freedoms of the LGBTQIA+ community.”

Sanders posted last week on social media that 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 himself vowed, “This is a campaign to reshape the Democratic Party.”

In Mills’ campaign video announcement, she made no mention of Platner and instead focused all her attention on attacking President Donald Trump, making hay out of a February moment in the national spotlight in which Trump warned the National Governors Association that he would withhold federal funds from states that didn’t comply with his executive order barring transgender athletes from women’s sports, to which Mills replied, “See you in court.” A court later ruled in Mills’ favor, and the Trump administration backed down.

While Trump is unpopular in Maine and Mills is staking her campaign on opposing him, the particular battle she highlighted might backfire inasmuch as nearly two-thirds of Mainers oppose transgender girls on girls’ sports teams, according to a poll in March by the University of New Hampshire Survey Center.

In her video, Mills attempted to tie Collins to Trump, noting Collins voted to confirm U.S. Supreme Court Justice Brett Kavanaugh, who helped overturn Roe v. Wade , and claiming Collins is assisting Trump as he “rips health care away from millions of Americans” and “gives corporate CEOs a massive tax cut.” Collins, however, is openly pro-choice and voted against Trump’s “big beautiful bill,” although she backed Trump’s tax cuts in 2017.

Collins, 72, has been in the Senate since 1996, and her middle-of-the-road, Maine-centric orientation has made her popular even though Maine is a blue state. She voted to convict Trump in his second impeachment trial and sided with Biden 67% of the time in the 117th Congress. She was one of only three Republicans to vote to confirm U.S. Supreme Court Justice Ketanji Brown Jackson and was the only Republican senator to vote against Justice Amy Coney Barrett.

In 2020, Collins defied the polls and won reelection by eight points, even as Biden carried the state against Trump by nine points.

Democrats need a net pick-up of four seats to flip the Senate next year, and Maine is critical to that calculus — it’s the only state where a Republican is up for reelection that voted for Kamala Harris in 2024.