Maine Gov. Janet Mills set to challenge Susan Collins for US Senate seat

By Sarah Ferris, Arit John, CNN

(CNN) — Maine Gov. Janet Mills is expected to announce her bid for US Senate on Tuesday, becoming the most high-profile Democrat to date to enter the race to challenge GOP Sen. Susan Collins, according to a source familiar with the plans.

The announcement date, the source cautioned, could shift due to the ongoing government shutdown.

Mills, a two-term governor and former attorney general, is a major recruit for Democrats looking for a seasoned opponent to take on the five-term incumbent. Senate Minority Leader Chuck Schumer spoke with her earlier this year about running.

But Mills is joining a crowded field of political novices, some of whom have vowed to stay in the race whether she ran or not. The Democratic primary will test how strongly voters in the state value experience over generational change.

Mills’ top opponents – oysterman Graham Platner, brewery owner Dan Kleban and former US House staffer Jordan Wood – have never held political office but argue they understand the affordability challenges facing Maine voters better than Collins, the 72-year-old incumbent.

Mills, 77, would be the oldest freshman senator in US history if she won, but also has a proven record of winning statewide.

And at a time when Democrats are also looking for fighters to stand up to President Donald Trump, Mills has shown a willingness to push back on the administration. During a meeting between the president and governors earlier this year, Mills sparred with Trump over transgender athletes and federal funding.

Any chance Democrats have of winning back the Senate or narrowing Republicans’ three-seat majority likely runs through Maine. Collins is the only Republican senator up for reelection next year in a state then-Vice President Kamala Harris won in 2024.

Democrats acknowledge that Collins, who was first elected to the Senate in 1996, will be difficult to beat. In 2020, Democrats saw an opportunity to oust her by capitalizing on anger over her vote to confirm Supreme Court Justice Brett Kavanaugh. Millions were poured into a fund to back an eventual Collins’ challenger, and Democrats avoided a messy primary by rallying around former Maine House Speaker Sara Gideon.

Collins was reelected by nearly nine points even as President Joe Biden won the state by a similar margin.

Democrats have notched prominent recruits in North Carolina, where former two-term Gov. Roy Cooper will run for an open seat. And in Ohio, former Sen. Sherrod Brown is running against Sen. Jon Husted, who was appointed earlier this year to the seat formerly held by Vice President JD Vance.

The-CNN-Wire
™ & © 2025 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.