Maine’s two-term Democratic Gov. Janet Mills plans to run next year for the Senate seat held by veteran Republican Sen. Susan Collins, two people familiar with Mills’ plans said Friday.
The development opens up a potential showdown between the two parties’ most prominent figures in a state where Democrats see a chance to pick up seats as they struggle to win a Senate majority.
Mills tentatively plans to announce his candidacy on Tuesday, the people said, but insisted on anonymity to discuss plans he was not authorized to share publicly.
Mr. Mills was the front-runner among national Democrats who had long sought to unseat Mr. Collins, who had held the seat since 1997. He had been urged to run by party leaders, including New York Sen. Chuck Schumer, the Senate minority leader. And although she only met once with Mr. Schumer earlier this year to discuss the race, her decision is being seen as a recruiting victory for Democrats, who also have prominent figures with statewide experience running for Republican-held seats in North Carolina and Ohio.
Democrats consider the Maine seat particularly important, given that it is the only seat on the 2026 Senate election calendar in which a Republican is defending an incumbent in the state, which was won by Democratic presidential candidate Kamala Harris last year.
Still, it remains a difficult proposition for Democrats to gain a majority in the 100-member Senate.
The party needs to win a net four seats, but most of the states that will hold Senate elections next year are areas where Republican Donald Trump defeated Harris. Maine is an exception, with former Democratic Gov. Roy Cooper considered a candidate in North Carolina, which Trump narrowly won, and former Democratic Sen. Sherrod Brown in Ohio, which Trump won comfortably and Brown lost in November.
In February, Mills gained national attention during a meeting of state governors with President Trump at the White House when she said, “We’ll see you in court” over her opposition to Trump’s call to deny states federal funding for transgender rights.
Maine officials sued the Trump administration in April to block the federal government from freezing federal funding to the state over its decision to defy a federal ban on allowing transgender students to participate in sports.
“I’ve spent most of my career listening to loud men talk tough to hide their weaknesses,” Mills said in April about the lawsuit, stoking Democratic enthusiasm.
Mills, 77, is a former state attorney general who also ran for governor in 2018 and 2022. Maine governors are barred from seeking a third term, and Mills appeared to dismiss a Senate campaign earlier this year, but he reconsidered that idea and said he was “seriously considering” running.
She had set a November deadline for making a decision, but as of mid-September she was interviewing potential campaign manager candidates.
A campaign against Collins would put her at odds with a senator who has built a reputation as a moderate but is also a key supporter of Trump’s cabinet and attorney general nominees. A Collins spokesperson declined to comment on Mills’ expected announcement.
Collins, 72, has won by double-digit percentages in all four of his re-election efforts, except for 2020.
That year, Collins defeated Democratic challenger Sara Gideon, a former speaker of the Maine House of Representatives, by more than 8 percentage points in a race that Democrats believed could help them win the Senate seat. With Collins’ victory, Democrats gained a net three seats in the House over the past year. She won despite Trump losing Maine to Democrat Joe Biden by 9 percentage points.
Like Collins, Mills was born in rural Maine. She became Maine’s first female criminal prosecutor in the mid-1970s, later elected as the state’s first female district attorney, and its first female attorney general and governor. She served as Attorney General twice, from 2009 to 2011 and from 2013 to 2019.
Several other challengers have announced their candidacy for the Democratic nomination, including oyster farmer Graham Platner, who has launched an aggressive social media campaign. Mr. Platner has the support of Vermont Sen. Bernie Sanders, who posted on social media Thursday that Mr. Platner is a “great working-class candidate for the Maine Senate to beat Susan Collins” and that it is “unfortunate that some Democratic leaders are encouraging Governor Mills to run.”
Whittle and Beaumont contributed to The Associated Press, reporting from Portland and Des Moines, respectively. AP writer Seung Min Kim in Washington contributed to this report.
