The 2026 United States Senate election in Maine will be held on November 3, 2026, to elect a member of the United States Senate to represent the state of Maine. Incumbent Republican Senator Susan Collins has not stated whether she will run for re-election to a sixth term in office.
This will be the only Republican-held Senate seat up for election in 2026 in a state that Kamala Harris won in the 2024 presidential election. Collins is the only incumbent Republican senator in any of the 19 states that Donald Trump did not win in any of his three elections.[1]
Collins was first elected in 1996 and was re-elected in four subsequent elections, significantly outperforming other Republicans in the state. In 2020, despite almost all polls and analysts predicting that she would lose her re-election bid, Collins unexpectedly defeated Democratic nominee Sara Gideon by about eight percentage points. Democratic presidential nominee Joe Biden carried Maine by about nine percentage points on the same ballot.[5]
As the only Republican-held Senate seat up for election in a state that Kamala Harris won in the 2024 presidential election and Collins' record of overperformance despite the state's Democratic lean, Maine is considered a key Senate battleground in 2026. This Senate seat has been held by Republicans since 1979, when Collins' predecessor, Republican William Cohen, defeated incumbent Democrat William Hathaway. Cohen's victory over Hathaway is the last time an incumbent U.S. Senator has been defeated for re-election in Maine.
With the decline of ticket splitting and being in a midterm year with a Republican president, Collins is widely viewed as the most vulnerable incumbent Republican senator.[6][7] Following the retirement of Joe Manchin and the defeats of Democratic senators Jon Tester and Sherrod Brown in 2024, Collins remains the last senator to represent a non-swing state of the opposite party (i.e., a reliably red or blue state).
Republican primary
Collins was first elected in 1996. While she has the firm backing of national Republicans,[8] two conservative Republicans are challenging Collins in the primary.[9]
On August 19, 2025, Sullivan Harbor Master Graham Platner announced his candidacy,[17] receiving the support of organized labor and Vermont Senator Bernie Sanders.[18] Progressive and younger Democratic Senators like Elizabeth Warren, Chris Murphy, Sheldon Whitehouse and Andy Kim have also expressed support for Platner's candidacy while stopping short of endorsing in the primary, as of October 2025.[19][20]Term-limitedGovernorJanet Mills was seen as a potential candidate to challenge Collins for months, with many National Democrats (including Senate Minority LeaderChuck Schumer, Kirsten Gillibrand and the DSCC) encouraging her to run,[21][22][23][24] though others, like Sanders, have publicly discouraged her from running.[25] Leaked campaign documents indicated that Mills was going to formally announce a campaign,[26] with Mills officially announcing on October 14 that she would challenge Collins in 2026, despite concerns from some about her age.[27][28] Mills would be the oldest freshman Senator in history, at 79 years old at the start of the term, should she be elected.[29] Mills has said she plans to serve one term should she be elected.[30] Several other Democrats have also announced campaigns.
↑ Kondik, Kyle (December 5, 2024). "The End of the Line for Red State Senate Democrats". Sabato's Crystal Ball. Retrieved July 9, 2025. Collins is now the lone outlier among all 100 senators as someone who continues to hold a Senate seat in a state that hasn't supported her party's presidential nominee in decades. Such outliers were important parts of past recent Democratic Senate majorities, but they will now be all gone.
↑ Hart, Benjamin (October 16, 2025). "Graham Platner's Honeymoon Is Over". Intelligencer. Retrieved October 17, 2025. Whether Platner can surmount any fallout from the posts may depend on how well he can incorporate them effectively into his regular-guy image — and whether there is more from his past to be exposed. One good sign for him: Two of his backers in the Senate seem unperturbed so far:
↑ "Jordan Wood". Patriotic Millionaires. Retrieved October 18, 2025.
1 2 Davis, Emma (September 3, 2025). "Maine Beer Company founder joins race against Susan Collins". Maine Morning Star. Retrieved September 5, 2025. After launching his campaign, Kleban announced later Wednesday Maine Senate President Mattie Daughtry and Lucas St. Clair, national board chair of the Trust for Public Land, as his campaign co-chairs.
↑ Razor, Calen; Carney, Jordain (October 9, 2025). "Graham Platner has a growing Senate fan club". Politico. Retrieved October 9, 2025. King said Wednesday that his general practice is not to campaign against colleagues, and he expects to stick with that next year — including not endorsing in the primary.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
