Maine’s two-term Democratic Gov. Janet Mills announced Tuesday she will run for her state’s U.S. Senate seat in 2026 in a bid to unseat five-term incumbent Sen. Susan Collins.
The race could be one of the most closely watched and hotly contested in the country as Republicans work to hold onto their majority in the Senate. Thirty-three seats are up for grabs in 2026, 20 of them held by Republicans. Of those 20, Maine is the only GOP-held Senate seat in a state that former President Donald Trump did not win in 2024. Democrats need to gain four seats to take the majority.
Even with Republicans defending 20 seats next year, and with the historical trend of the party not in power often performing better in midterms, Democrats still face long odds of reclaiming the Senate. But Maine’s Senate seat is seen as a must-win for Democrats if they hope to retake the chamber.
Collins has long been considered one of the Senate’s more moderate Republicans. She has often broken with her party in key votes, including being one of only seven Republicans who voted to convict Trump in 2021 during the Senate’s impeachment trial following the Jan. 6, 2021, attack on the U.S. Capitol.
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She has, however, voted with her party on several key measures this year, including the Big Beautiful Bill Act. She also voted to confirm several of Trump’s more controversial nominees, including Health and Human Services Secretary Robert F. Kennedy Jr., but opposed Trump’s pick to lead the FBI, Kash Patel.
Mills sought to cast Collins as an ardent supporter of Trump’s agenda when launching her campaign.
"I’ve never backed down from a bully and I never will," Mills said. "Donald Trump is ripping away health care from millions, driving up costs, and giving corporate CEOs massive tax cuts. And Susan Collins is helping him."
While Mills appears focused on a general election showdown with Collins, she still faces potential competition in the Democratic primary. Graham Platner has gained prominence thanks to major early endorsements, including from Sen. Bernie Sanders. Last week, Sanders suggested Mills should not run for the seat.
"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," he wrote on X.
