Maine Gov. Mills will announce challenge to Sen. Collins in key 2026 Senate contest, AP sources say

PORTLAND, Maine (AP) — Maine’s two-term Democratic Gov. Janet Mills will run for the U.S. Senate seat held by veteran Republican Sen. Susan Collins next year, according to two people familiar with Mills’ plans on Friday, setting up a potential matchup between the parties’ best-known figures in a state where Democrats see a chance to gain a seat in their uphill quest for the majority.

Mills was the top choice of national Democrats to try to unseat Collins, who has held the seat since 1997, and was urged to run by party leaders including Sen. Chuck Schumer, the minority leader. Her entry in the race is another recruiting win for Democrats, who also have well known Democrats with statewide experience looking to pick up GOP-held seats in North Carolina and Ohio.

Democrats see Maine as an important target, considering it is in the only place on the 2026 Senate election map where Republicans are defending an incumbent in a state carried last year by Democratic presidential nominee Kamala Harris.

Democrats need to pick up a net of four seats to retake the majority, but doing so remains difficult, as most of the Senate seats on the ballot next year are in states President Donald Trump won easily.

Mills, 77, was elected governor in 2018 and reelected in 2022. Maine governors are barred from seeking third terms and, while Mills early in the year seemed to dismiss running for Senate, she had said in late summer she was “seriously considering” running for the office.

The former Maine attorney general sparred with Trump during a February White House meeting of governors and the president, telling him, “We’ll see you in court,” in her opposition to his call for denying states federal funding over transgender rights.

In April, Maine officials sued the Trump administration in an effort to stop the federal government from freezing federal funding to the state in light of its decision to defy a federal ban on allowing transgender students from participating in sports.

Mills stoked Democratic enthusiasm in April when she said of the lawsuit, “I’ve spent the better part of my career listening to loud men talk tough to disguise their weaknesses.” A campaign against Collins would pit her against a senator who has built a reputation as a moderate, but was a key supporter of Trump’s Cabinet and judicial nominations.

Collins has won all of her four reelection campaigns by double-digit percentages, except for in 2020.

Collins defeated Democratic challenger Sara Gideon, the former speaker of the Maine House of Representatives, in 2020 by fewer than eight percentage points in a race that Democrats felt would help them pick up a seat in the Senate. Collins won that race in a year Democrats made a net gain of three seats in the chamber. And she won in spite of a poor showing by Trump at the top of the ticket.

Like Collins, Mills was born in rural Maine. She became Maine’s first female criminal prosecutor in the mid-1970s, and would later become the state’s first elected female district attorney as well as its first female attorney general and governor. She served as attorney general twice, from 2009 to 2011 and 2013 to 2019.

A few other challengers have declared candidacies for the Democratic nomination, including oyster farmer Graham Platner, who was launched an aggressive social media campaign. Platner has the backing of Vermont Sen. Bernie Sanders, who posted on social media on Thursday that Platner is “a great working class candidate for Senate in Maine who will defeat Susan Collins”