Maine Gov. Janet Mills announced her candidacy for U.S. Senate on Oct. 14, setting up a race that may serve as a proxy for the direction of the Democratic party.
Mills, 77, is joining a crowded field of Democrats looking to take on incumbent Sen. Susan Collins, a rare Republican representing a state that has voted largely Democratic in each of the past three presidential elections.
That field includes Jordan Wood, a former chief of staff to U.S. Rep. Katie Porter, D-Calif., and David Costello, the Democratic nominee for U.S. Senate in 2024 against Sen. Angus King.
But the candidate that has garnered the most national attention is Graham Platner, a political newcomer that has gained the support of progressive leaders like Sen. Bernie Sanders.
The race between Mills, a 77-year-old experienced politician, and Graham, a 41-year-old oysterman, may serve as a proxy for the battle over the direction of the party.
“I think there’s kind of, is, this is kind of a soul searching for Democrats. What do we want as a party?” said Jim Melcher, a professor of political science at the University of Maine at Farmington. “I think it’s also, to some extent, the referendum on the party.”
Gov. Janet Mills gave her inaugural address at the Augusta Civic Center after being sworn in for a second term.
Other candidates in the Democratic primary include fashion designer Natasha Alcala; former Department of Defense policy writer David Evans; former Army veteran Tucker Favreau; University of Maine professor Andrea LaFlamme; and former contracting officer for the U.S. Air Force Daira Smith-Rodriguez.
The age issue haunting the Democratic party
Mills, who has been governor for two terms and is term-limited in 2026, has been a fairly popular governor and has a record of combatting President Donald Trump, gaining national attention for clashing with him over transgender rights earlier this year. But she is 77 and, if elected, would be the oldest ever freshman senator.
The Democratic party has been facing backlash over the age of its elected leaders, especially following former President Joe Biden dropping out of the 2024 race due to questions about his age. In Massachusetts, Rep. Seth Moulton is challenging Sen. Ed Markey for his seat specifically because of his age and seniority, and similar challenges are happening throughout the country.
“Age is kind of a proxy for some other things. I think certainly, Governor Mills is very vigorous, whether people like her or not, I don’t think anybody’s been questioning her mental fitness,” Melcher said. “Age I think matters so much because it’s partly a proxy for change. That it’s not just about how old Janet Mills is, it’s how long she’s been around, that she, I think, to some people, represents where the party was before, and that they want something else.”
Platner is much younger than Mills and is ideologically to her left (he has said there is a “U.S.-funded genocide in Palestine”). He has quickly gained traction, raising over $4 million and getting the endorsement of Sanders, who also encouraged Mills to stay out of the race.
Maine Gubernatorial candidate Troy Jackson, U.S. Sen. Bernie Sanders, and Graham Platner, who is challenging Republican U.S. Sen. Susan Collins, held a Labor Day rally at the Cross Insurance Arena in Portland, Maine on Sept. 1, 2025.
Platner appears to be fighting to be the face of “something different,” Melcher said, and could consolidate the support of those who don’t want a traditional candidate, who want somebody younger or who want someone more progressive.
Is this the year to defeat Susan Collins?
Collins has been resilient in Maine since first getting elected in 1997, most recently defeating a well-funded Democratic challenger in 2020.
She has long found success as a moderate Republican who occasionally bucks her party. But Melcher thinks that perception might have changed in the Trump era, when there are a fair number of Republicans who say she doesn’t support Trump enough and Democrats who say she’s gone along with Trump too much.
An April University of New Hampshire Survey Center poll found that 71% of Mainers, including majorities of all parties, think Collins does not deserve to be re-elected.
Non-presidential election years for the president’s party also tends to lead to losses for that party, Melcher said, although that tends to be truer for House elections.
Who has the better chance of defeating Collins, Mills or Platner?
Mills and Platner have different advantages and disadvantages in a race against Collins, according to Melcher. Mills, in many ways, is very electable: she’s well known, has higher popularity, has won statewide before and is from a prominent Maine family.
However, younger voters may not want to turn out for her and some on the left may think she’s not progressive enough, things Platner can take advantage of.
But Platner’s popularity is unpredictable, and Melcher said that centrists tend to win in Maine.
After Mills entered the race, the non-partisan Cook Political Report changed its rating of the Maine Senate race from “lean republican” to “toss-up.”
Of course, both say that they are the right choice.
“I’m the only one in this campaign who’s actually stood up to Donald Trump, and I’ll do it again,” Mills said on social media. “Susan Collins has bowed down to Trump. So I’m running for Senate to replace her—and I’m the only one who can beat her.”
Platner, predictably, had a different take.
“This is a generational race. It’s about old ideas vs new ideas,” Platner posted Oct. 15. “About whether Democrats win by fighting for serious structural change — or lose to Susan Collins yet again by doing more of the same.”
This article originally appeared on Portsmouth Herald: Janet Mills vs Graham Platner: What to expect in Maine’s 2026 Senate race
