If Democrats hope to win back control of the Senate, their path runs through Maine. 

Republican Susan Collins, a Maine institution, has represented the state in the Senate since 1997 and is the only Republican senator in a state that reliably votes for Democrats at the presidential level.

Collins, 72, has indicated she plans to seek a sixth term in office but has not yet made a formal announcement. She’s broken with her party and President Donald Trump on key issues — in Trump’s second term, she voted against confirming some of his high-profile nominees and voted against passing his sprawling tax cut and spending package that included deep cuts to social programs used by the poorest Americans. White House officials have discussed backup candidates who could run for the Republican nomination in Maine if Collins opts not to run for reelection, Politico reported. 

Even as Maine has trended increasingly Democratic, unseating Collins at the ballot box has historically been a tall order that many Democrats have attempted and failed. In 2020, Democratic nominee Sara Gideon raised a staggering $74 million and spent $62 million to lose to Collins by over eight points. 

The 2026 Maine Senate race is currently in a holding pattern awaiting decisions from Collins and Democratic Gov. Janet Mills, who is term-limited and widely seen as Collins’ strongest challenger. David Costello, who ran as a Democrat in 2024 against Sen. Angus King, an Independent who caucuses with Democrats, and Jordan Wood, a Lewiston native and ex-chief of staff to former Rep. Katie Porter of California, have entered the Democratic primary so far.  

Several other high-profile Maine Democrats, including Secretary of State Shenna Bellows, former Maine Senate President Troy Jackson and former Maine Speaker of the House Hannah Pingree, are running for governor instead. And Rep. Jared Golden, who represents the competitive 2nd District, opted to run for reelection to his House seat instead of running for Senate or governor.  

Republicans currently control the Senate by a three-seat majority, 53 to 47, and senators serve six-year terms, meaning a third of the Senate is up every election cycle. For Democrats to win back the chamber in 2026, they’d need to hold on to every seat they have, including competitive ones in Georgia and Michigan. They also would have to flip four GOP-held seats — targets include  Maine, North Carolina and even more Republican-leaning states such as Ohio, Iowa, Nebraska and Texas.