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, first elected in 1996, is running for re-election to a sixth term in office. If elected, Collins will become the longest-serving U.S. Senator from Maine, surpassing William P. Frye on May 26, 2027.
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. Both the Democratic primary and general election are expected to be some of the most competitive races in the Senate election cycle.
This election will coincide with U.S. House elections for Maine's two congressional districts, a gubernatorial election, and various other state, county and local elections. The primary is scheduled to take place on June 9, 2026. Both the primary and general elections will be conducted with ranked-choice voting.
The northernmost state in New England, Maine is one of the most rural states in the nation, and is considered to be a moderately blue state, having voted for every Democratic presidential nominee since 1992, and voting for Kamala Harris by about seven percentage points in 2024. Democrats also control the governorship, the state legislature, and both seats in Maine's U.S. House congressional delegation. Furthermore, after Jared Golden defeated Bruce Poliquin in Maine's 2nd congressional district in 2018, Collins has been the only Republican representing any state in New England at the federal level, in either chamber of Congress.
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 nine percentage points. Democratic presidential nominee Joe Biden carried Maine by about nine percentage points on the same ballot.
As the only Republican-held Senate seat up for election in a state won by Kamala Harris in the 2024 presidential election, Maine is considered a key Senate battleground in 2026 despite Susan Collinsâ history of electoral overperformance. Republicans have held the seat since 1979, when William Cohen defeated incumbent Democrat William HathawayâÂÂthe last time a sitting U.S. senator from Maine lost reelection. No Democrat has won a Maine Senate race since George J. Mitchell was reelected in 1988, or this seat since HathawayâÂÂs election in 1972.
With the decline of ticket splitting, and being in a midterm election with an unpopular Republican president, Collins is widely viewed as the most vulnerable incumbent Republican senator. Following the retirement of Joe Manchin in West Virginia, and the defeats of Democratic senators Jon Tester in Montana and Sherrod Brown in Ohio in 2024, Collins remains the last senator to represent a non-swing state of the opposite party (a reliably red or blue state).
Incumbent U.S. senator Susan Collins officially announced her reelection bid in February 2026. Despite conservative backlash to her centrist voting record, the Republican Party has supported her reelection. However, she faced a primary challenge from former police officer Dan Smeriglio, a critic of her bipartisan approach. Ultimately, Collins was the only Republican to qualify for the primary ballot.
In April 2025, former congressional staffer Jordan Wood became the first Democrat to enter the race, running on a platform opposed to the Trump administration and Elon Musk. On August 19, Sullivan Harbor Master Graham Platner launched a progressive campaign backed by Bernie Sanders and organized labor, positioning himself against the âÂÂDemocratic establishmentâ and drawing support from both liberal voters and some 2024 Trump voters.
Governor Janet Mills was widely viewed as a top Democratic recruit, with encouragement from national figures including Senate Minority Leader Chuck Schumer, Senator Kirsten Gillibrand, and the Democratic Senatorial Campaign Committee (DSCC), though Sanders publicly discouraged her candidacy. After weeks of speculation and leaked campaign plans, Mills entered the race in October 2025, pledging to serve only one term; her age, 79 at the start of the term, drew some scrutiny. The DSCCâÂÂs close involvement in her campaign, including a joint fundraising committee, prompted backlash and allegations of favoritism in the primary.
Following her entry, several candidates, including Dan Kleban and Daira Smith-Rodriguez, withdrew and endorsed Mills. Smith-Rodriguez cited concerns over past comments by Platner regarding sexual assault in the military. Wood later withdrew to run for the U.S. House.
In January 2026, Platner briefly paused his campaign due to his wifeâÂÂs medical treatment abroad before resuming later that month, returning to the trail with protests against Immigrations and Customs Enforcement (ICE) enforcement actions.
By early 2026, Mills committed to multiple debates ahead of the June 9 primary, while Platner secured endorsements from Senators Martin Heinrich, Elizabeth Warren, and Ruben Gallego, the latter of whom also questioned Millsâ general election viability.
Although several Democrats initially filed, only Mills, Platner, and 2024 nominee David Costello qualified for the primary ballot. In addition, University of Maine adjunct professor Andrea LaFlamme is mounting a write-in bid for the Democratic nomination.
Despite multiple controversies, polling has consistently shown Platner leading Mills in the primary and incumbent Senator Susan Collins in a potential general election matchup.
Shortly after Mills entered the race, Platner came under fire for resurfaced controversial Reddit posts, resulting in his campaign's political director, former state representative Genevieve McDonald, quitting the campaign and calling Platner "unelectable"; however, Democratic National Committee Chair Ken Martin stated that the comments were not disqualifying, and Platner apologized in a five-minute video posted to social media. On October 21, Platner released a video of himself dancing and singing shirtless at his brother's wedding, revealing he had a chest tattoo that resembled the Totenkopf used by Nazi Germany's Schutzstaffel. Platner stated he got the tattoo while inebriated with other U.S. Marines while stationed in Croatia, mistaking the symbol for a generic skull and crossbones. He had the tattoo covered, and professed his shame and disgust for getting a tattoo that resembled the fascist insignia. Platner also called himself an anti-fascist "supersoldier" in an old Reddit comment. After the controversies, Democrats such as Senator Chris Murphy defended Platner and said that he "sounds like a human being" who is honest about his mistakes and Senator Gallego called his campaign "authentic" and said that he has "the right to grow out of his stupidity" and is not going to be a "crypto Fetterman".
On February 26, 2026, Platner quote-tweeted a clip from Donald Trump's 2026 State of the Union Address, criticizing Trump's speech. The clip had been posted by anti-Semitic white supremacist Stew Peters. The tweet was deleted hours later, with a spokesperson for Platner's campaign telling The Hill that they were unaware of Peters' views.
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Susan Collins vs. Janet Mills
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Susan Collins vs. Graham Platner
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