Maine Senate Race 2026

Compare candidates running in this Maine federal race. Review their positions, voting records, campaign promises, and donor information.

Susan Collins

Party: Republican

David Costello

Party: Democrat

Graham Platner

Party: Democrat

Janet Mills

Party: Democrat

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Maine Senate Race

Election: Nov 3, 2026Updated: Apr 6, 2026
📊Polling+7.0 Platner
In hypothetical general election matchups tested in March 2026, Graham Platner leads Collins by 7 points (48-41%), while Janet Mills leads by 3 points (46-43%). Polling shows high variability depending on which Democrat emerges from the June 9 primary.
Source: Emerson College Polling2026-03-23
48%
Platner
41%
Collins
toss up★ Flip Potential— Cook Political Report|Sabato

Maine is Democrats' clearest offensive pickup opportunity in 2026 and essential to retaking Senate control. As the only Republican-held seat in a Kamala Harris-won state, flipping Collins' seat is viewed as virtually necessary for Democrats to reach the 51 votes needed for majority control.

Susan CollinsR
David CostelloD
Graham PlatnerD
Janet MillsD

Summary

Susan Collins, 73, is Maine's senior senator who has represented the state since 1997 and is seeking her sixth term. Born in Caribou, Aroostook County, she is a graduate of St. Lawrence University in New York. Collins began her career as a staff assistant for Senator William Cohen (1975-1987), then served in various Maine administrative roles before being elected to the Senate in 1996. She is the chair of the Senate Appropriations Committee and has served in leadership positions in multiple Senate committees. Collins has built a reputation as a moderate Republican willing to break with her party on key votes, though her voting record shows increasing alignment with Trump administration priorities. She is the only Republican senator representing a state won by Kamala Harris in 2024 and has won all five previous Senate elections, often significantly outperforming other Republicans in Maine.

David Costello, 65, is an Old Town native with over 30 years of government experience. He previously ran for independent Senator Angus King's seat in 2024, receiving 11% of the vote. Costello served as senior aide to Maryland's governor (2007-2011), led the Maryland Department of the Environment (2011-2015), worked for the U.S. Agency for International Development (USAID) in conflict-torn regions, and served as interim climate and clean energy program director for Maine's Natural Resources Council. His 2026 campaign emphasizes substantive reform agenda and governance experience, positioning himself between Mills and Platner as a serious policy-focused candidate without their controversies.

Graham Platner, 41, is an oyster farmer, Marine Corps veteran (with three Iraq deployments), and Army National Guard veteran (one Afghanistan deployment) from Sullivan, Maine. He launched his campaign in August 2025 with a viral video criticizing the 'oligarchy' that generated 2.5 million views in 24 hours. Platner is backed by Bernie Sanders and positioned himself as a progressive populist challenging the Democratic establishment. Despite controversies over old social media posts and a Nazi-linked tattoo, he has led Mills in most polling and significantly outraised her in fundraising. His campaign emphasizes grassroots organizing with over 50 town halls across Maine.

Janet Mills, 78, is the outgoing Maine Governor who served two terms (2019-2027). Born in Farmington, she co-founded the Maine Women's Lobby in 1978 to advocate for abuse survivors. She served as district attorney for three Maine counties, Maine Attorney General (2009-2011, 2013-2019), and Maine House Representative. Mills was recruited by Senate Minority Leader Chuck Schumer and national Democratic leaders to run for Senate. She entered the race in October 2025, pledging to serve only one term. Her campaign emphasizes her executive experience and track record of standing up to President Trump, particularly over transgender athlete protections in schools.

Campaign Promises

Other
  • Continue bipartisan problem-solving and pragmatic governance
  • Approach issues with pragmatism rather than ideology
  • Support both Republican and Democratic positions when warranted
Economy
  • Deliver for Maine through seniority and committee positions
Other
  • Strengthen democracy through substantial institutional reform
  • End partisan gridlock through reform and strong leadership
  • Expand federal food, health and education programs
Justice
  • Codify abortion rights protections from Roe v. Wade
Environment
  • Address climate change through government action
Healthcare
  • Improve healthcare access and affordability
Education
  • Provide universal pre-kindergarten and after-school care
Healthcare
  • Medicare for All / Universal healthcare
Other
  • Ban billionaires from buying elections
  • Housing affordability and ending U.S. involvement in foreign wars
Immigration
  • Support path to citizenship and end mass deportation
Economy
  • Pass the PRO Act to strengthen labor unions
  • Implement a billionaire minimum tax
  • Protect Maine's working waterfront and commercial fishing
Justice
  • Support strong federal guarantee of abortion rights
Economy
  • Fix what's broken in Washington, lower costs for everyone
Justice
  • Fight Trump and protect reproductive rights
  • Support transgender youth rights
Healthcare
  • Expand healthcare access

Key Issue Positions

Bipartisan reputation vs. record of supporting Trump priorities
Collins claims to maintain independence while her voting record shows increasing alignment with Trump and Republican positions
Collins has been ranked the most bipartisan senator by the Lugar Center and Georgetown University. However, she voted to confirm multiple Trump Supreme Court justices (Roberts, Thomas, Alito, Gorsuch, Kavanaugh, Jackson) and supported Trump cabinet nominees. She also voted for the Kavanaugh confirmation despite claiming he misled her about Roe v. Wade, and she voted against a measure to constrain Trump's Iran war authority.
Independent vs. party line voting
Collins frames herself as independent but often votes with Republicans
She has broken with Republicans on some votes (notably voting to convict Trump in second impeachment trial attempt and supporting gun background checks), but her overall voting alignment with Republicans is strong.
Approval ratings and vulnerability
Collins' approval ratings have fallen significantly, making her the most vulnerable Republican incumbent
Morning Consult polling showed only 36% of Mainers approved of Collins in October 2025. Her approval has declined as Republicans' Maine presence has eroded. However, Collins has consistently outperformed expectations in elections.
Support for ICE funding and mass deportation enforcement
Collins negotiated bipartisan DHS spending that increased ICE funding, though she claims to have included accountability measures
Collins helped negotiate a bipartisan Homeland Security funding bill that would increase funding for ICE and CBP by billions without significant new restraints, though it included funding for body cameras and de-escalation training. Democrats have attacked this as enabling Trump's mass deportation efforts.
Democratic institutional reform focus
Costello argues fixing democracy itself is prerequisite for addressing other issues
Unlike Mills (who emphasizes experience) and Platner (who emphasizes economics), Costello's entire platform rests on institutional reform: Electoral College elimination, campaign finance overhaul, House expansion, Senate restructuring, Supreme Court term limits, and making amending the Constitution easier.
Low name recognition and polling
Costello remains largely unknown in Maine despite significant government experience
Polling shows Costello consistently in single digits (4% in recent polls), far behind Mills and Platner. This reflects limited visibility despite his substantive background.
No controversies
Costello's campaign has been notably free of scandal or controversy
Unlike Platner, Costello has not faced attacks over past statements or behavior. Unlike Mills, he hasn't faced questions about age or establishment backing. His main weakness is obscurity, not controversy.
Controversial past social media posts and Nazi-linked tattoo
Platner has apologized and disavowed all controversial statements, attributing them to PTSD and personal struggles post-military service
In 2013, Platner made Reddit posts dismissing sexual assault concerns, calling himself a 'communist,' writing that all cops are bastards, and agreeing rural white Americans are racist and stupid. He also has a skull-and-crossbones tattoo from military service that resembles Nazi imagery, which he has since covered. Mills has built her primary campaign heavily around these controversies with attack ads.
Fundraising from health care lobbyists while pledging to reject them
Platner fundraised with healthcare lobbyists days before signing a pledge to reject healthcare industry donations
In March 2026, Platner attended a coffee fundraiser with health care lobbyists in Washington, then signed the National Nurses United 'Patients Over Profits' pledge days later, promising to reject donations from healthcare executives and lobbyists. His campaign claims attendees came on their own behalf, not as industry representatives.
Quote-tweeted antisemitic content
Platner's campaign deleted a February 2026 retweet of a Trump State of the Union clip posted by white supremacist Stew Peters
On February 26, 2026, Platner quote-tweeted a clip criticizing Trump's speech, not realizing the original post was from antisemitic white supremacist Stew Peters. The tweet was deleted hours later with an apology. Platner's camp claimed they were unaware of Peters' views.
Self-described flexibility on healthcare fundraising
Platner claims his progressive healthcare message has remained consistent despite fundraising events
Platner's campaign notes that fundraising events held in March and December were not industry-specific events, and attendees came on their own behalf. His message of Medicare for All and breaking up healthcare monopolies has remained constant.
Age and electoral viability
Mills argues her experience and electoral track record outweigh age concerns
At 79 when she would take office, Mills would be the oldest freshman senator in U.S. history. She won her 2018 gubernatorial race by 7 points and her 2022 reelection by 13 points. However, some Democrats worry about her age and generational appeal.
Establishment backing
Mills is the Democratic establishment's preferred candidate
Recruited by Chuck Schumer and backed by the Democratic Senatorial Campaign Committee (DSCC). This establishment support has drawn backlash from progressive Democrats and supporters of her primary rival Graham Platner.
Policy agenda clarity
Campaign emphasizes biography and broad themes over detailed policy
Critics note Mills' campaign website lacks a dedicated policy page comparable to Platner's detailed platform. Her campaign focuses more on her experience and electability argument.

Top Donors

Large individual contributions
65.30% of fundraising from large individual contributionsIndividual
OpenSecrets data shows Collins relies heavily on large-dollar donors, contrasting with Platner's small-donor base.
PAC contributions
10.34% of fundraising from PACsPAC
Including corporate and trade association PACs.
AIPAC (pro-Israel PAC)
Nearly 20% of Collins' 2025 fundraising came from AIPACIndustry PAC
AIPAC accounted for nearly 20% of Collins' fundraising last year, more than she raised from small donors, illustrating pro-Israel lobby influence.
Palantir executives
$110,000+ from Palantir executives since 2006; significant 2026 contributions to Pine Tree Results super PACIndividual
Executives from Palantir (AI firm providing tools for mass deportation surveillance) have donated substantially to Collins and the Pine Tree Results super PAC supporting her.
James David (New Balance CEO)
At least $1 million donatedIndividual
New Balance CEO donated at least $1 million toward Collins' reelection campaign. Collins announced her reelection bid in a video using New Balance sneakers.
Blackstone Group
$97,050Industry PAC
Top contributor to Collins according to OpenSecrets data.
Dirigo PAC (Collins' Leadership PAC)
Contributions to Collins' own leadership PACLeadership PAC
Collins maintains her own leadership PAC to support other candidates and accumulate funds.
Campaign total
$10.4 million raised (as of January 31, 2026); $8 million cash on handMultiple sources
Collins has raised significantly more than either Democratic primary candidate and has the strongest cash position for the general election.
Small individual donors
$4 million total raised through December 2025, including $1.2 million in Q4Small Donor
Costello has approximately $632,000 cash on hand entering 2026. Significantly less than both Platner ($3.7M) and Collins ($8M).
Small individual donors
$7.8 million raised by end of 2025 (4th quarter alone: $4.6 million)Small Donor
99% of contributions $200 or less, averaging $25.88 in Q4 2025. Over 182,000 individual contributions. Campaign claims no corporate PAC donations.
Bernie Sanders
Endorsement (no direct funding from Sanders personally)Individual
Endorsed Platner on August 30, 2025, calling him 'a great working-class candidate for Senate in Maine who will defeat Susan Collins.'
United Auto Workers
Endorsement (no direct funding amount specified)Organization
Labor union endorsement supporting Platner's populist economic agenda.
Maine State Nurses Association
Endorsement (no direct funding amount specified)Organization
Labor union endorsement supporting Platner's healthcare and workers' rights positions.
U.S. Senator Bernie Sanders (I-VT)
EndorsementIndividual
Backed Platner early and prominently, creating opposition to Chuck Schumer's Mills endorsement.
U.S. Senator Martin Heinrich (D-NM)
Co-hosted fundraiserIndividual
Hosted fundraiser for Platner in early 2026, endorsing him over Mills.
U.S. Senator Elizabeth Warren (D-MA)
EndorsementIndividual
Endorsed Platner by early 2026.
U.S. Senator Ruben Gallego (D-AZ)
EndorsementIndividual
Endorsed Platner and also questioned Mills' general election viability.
Maine People's Alliance
Endorsement and organizing supportOrganization
Progressive advocacy group that endorsed Platner and helped organize grassroots support.
EMILY's List
Significant spending, exact amount in 2026 cycle pendingOrganization PAC
National group raising money for Democratic women candidates supporting reproductive rights. Endorsed Mills immediately upon her entry to the race and backed her 2018 gubernatorial primary.
Democratic Senatorial Campaign Committee (DSCC)
$1 million joint fundraiser within 24 hours of announcementParty Committee
Established joint fundraising committee with Mills' campaign, indicating strong party support and coordination.
Reproductive Freedom for All
Endorsement (direct funding amount not specified)Organization PAC
National abortion rights group. Endorsed Mills in December 2025, describing her as the only candidate with 'an unimpeachable record of expanding access' to reproductive care.
Small individual donors
$2.6 million raised (as of December 31, 2025)Small Donor
Mills' campaign has raised $2.6 million total and spent more than half, leaving $1.3 million cash on hand entering 2026. This lags significantly behind Platner's $7.8 million.

Contradictions

Claim: Collins portrays herself as an independent moderate who defies extreme philosophies
Contradiction: While Collins has broken with her party on some votes, her voting record increasingly aligns with Trump and Republican positions on major issues: Supreme Court confirmations, Iran war authority, Medicaid-cutting reconciliation bills, and transgender sports bans. Her 'independence' is more about rhetoric than consistent voting patterns.
Source: Congress.gov voting records, HRC ratings, Lugar Center bipartisan rankings, news coverage of her votes
Claim: Collins said she was misled by Kavanaugh about his views on Roe v. Wade precedent
Contradiction: After the Dobbs decision overturning Roe, Collins claimed Kavanaugh and Gorsuch 'misled' her about respecting stare decisis. However, she still votes to confirm other justices with similar views, and defended Roe codification attempts only weakly (voted no on Women's Health Protection Act due to lack of religious exemptions).
Source: Collins statements, voting records on judge confirmations and abortion bills
Claim: Collins negotiated bipartisan DHS spending that includes new ICE accountability measures
Contradiction: While the bill included body cameras and de-escalation training funding, it did not significantly restrict ICE operations and increased funding for the agency. Democrats argue the funding enables Trump's mass deportation operations that have killed U.S. citizens.
Source: Axios, Senate Majority PAC ads, Collins campaign memo responding to criticism
Claim: Collins has helped Maine with significant funding through her Appropriations Committee role
Contradiction: Collins secured $425 million in earmarks for Maine in 2026 budget bills. However, Democrats argue the overall Medicaid cuts and healthcare cuts in reconciliation bills harm Maine more than specific project funding benefits the state.
Source: Collins' own statements about funding; Democratic analysis of broader budget impact

No contradictions documented.

Claim: Platner claims to be a grassroots, anti-establishment candidate powered by small donors and not corporate PACs
Contradiction: While 99% of Platner's donations are $200 or less (averaging $25.88), he has also fundraised with health care lobbyists and has reportedly been 'scouted' by unions and progressive consultants. Morris Katz, a senior adviser to NYC Mayor Zohran Mamdani, produced his launch video. He has also accepted donations from Senator Martin Heinrich's fundraiser.
Source: Axios, Bangor Daily News, Common Dreams reporting on Platner's fundraising and campaign development
Claim: Platner says he voted for Susan Collins at least once, viewing her as a moderate
Contradiction: He now views Collins as 'just another self-interested, establishment politician' who uses the 'myth of moderation' to stay in power and doesn't deliver for Maine despite chairing the Appropriations Committee.
Source: NBC News interview with Platner in November 2025
Claim: Platner positions himself as a fighter against billionaires and corporate interests
Contradiction: His campaign has raised millions from higher-dollar events and has taken funds from sources that don't fit his anti-establishment narrative, despite the small-donor emphasis.
Source: Bangor Daily News reporting on fundraising events
Claim: Mills' campaign attacks Platner over old social media posts while her own campaign emphasizes biography and electability, not detailed policy
Contradiction: Mills has launched multiple negative ads targeting Platner's 2013 Reddit posts about sexual assault, yet her own campaign platform lacks the detailed policy specificity that Platner presents, raising questions about the focus on personal attacks versus policy contrast.
Source: Central Maine, Maine Public, NBC News, Bangor Daily News reporting on campaign tactics
Claim: Mills opposed to establishment politics, but is the DSCC's top recruit with strong establishment backing
Contradiction: While Mills frames herself as a fighter against Washington dysfunction, she was actively recruited by Senate Minority Leader Chuck Schumer and has the close involvement of the DSCC, prompting some backlash over favoritism in the primary.
Source: Wikipedia, NBC News, The Hill reporting on campaign recruitment and backing

What Opponents Say

Janet Mills and Democrats

Collins rubber-stamped all Trump judges who dismantled Roe, is a day late and a dollar short on standing up to Trump, and supports ICE mass deportation

Mills attacked Collins for confirming judges who overturned Roe, voting against Venezuela war powers measure, and negotiating ICE-funding DHS bill. Mills framed Collins as ineffectual at protecting Maine when it matters.

Graham Platner

Collins is 'just another self-interested, establishment politician' who uses the 'myth of moderation' to stay in power without delivering results

Platner criticized Collins' decades in Senate and argued she hasn't used her Appropriations gavel to deliver real benefits to Maine despite promising to when she got the position.

President Donald Trump

Collins 'should never be elected to office again' and is a 'disaster'

Trump attacked Collins for her vote on the Venezuela war powers resolution and called her unelectable, making her the subject of his most intense Republican criticism for her independence.

Mills campaign (implied)

Mills is more electable due to name recognition and electoral track record

Mills argues she has proven ability to win statewide elections, implicitly suggesting lesser-known candidates like Costello are less viable.

Platner campaign (implied)

Platner's populist agenda is more compelling than establishment-style governance reform

Platner's grassroots movement contrasts with Costello's technocratic governance approach, positioning Costello as too establishment-focused despite his policy focus.

Janet Mills

Platner is unelectable due to controversial past statements about sexual assault, and his candidacy is 'the fastest way to hand Susan Collins another Senate term'

Mills has launched multiple attack ads focusing on Platner's 2013 Reddit posts in which he downplayed sexual assault. Mills' campaign argues Platner should be defined by these statements and that his controversies make him too risky to win the general election.

Mills campaign surrogates (EMILY's List, Maine Democrats)

Platner belittles sexual violence and blames victims, making him unfit for office

EMILY's List president Jessica Mackler stated: 'Women in Maine refuse to send a man who belittles sexual violence and blames victims to the Senate.'

Republican National Committee

Platner is committed to a radical socialist agenda

The RNC characterized the Democratic primary as between 'extreme vs. more extreme,' attempting to tie both candidates to socialism, though specifically targeting Platner's more progressive platform.

Graham Platner

Mills represents establishment politics that has failed Maine

Platner and his campaign position Mills as an establishment-backed politician who benefits from DC insider support, while Platner runs as an anti-establishment populist candidate.

Republican National Committee

Both Mills and Platner are committed to a 'radical socialist agenda'

The RNC characterized the Democratic primary as a contest between 'extreme vs. more extreme,' attempting to tie both candidates to socialism.

Endorsements

Senate Minority Leader John Thune (R-SD)individual
Senate Leadership Fund (Republican super PAC)organization
President George W. Bushindividual
National Republican Senatorial Committeeorganization
Lugar Center and Georgetown University McCourt School of Public Policyorganization
No major endorsements reportedorganization
U.S. Senator Bernie Sanders (I-VT)individual
United Auto Workersorganization
Maine State Nurses Associationorganization
U.S. Senator Martin Heinrich (D-NM)individual
U.S. Senator Elizabeth Warren (D-MA)individual
U.S. Senator Ruben Gallego (D-AZ)individual
Maine People's Allianceorganization
Democratic National Committee Chair Ken Martinindividual
Senate Minority Leader Chuck Schumer (D-NY)individual
EMILY's Listorganization
Reproductive Freedom for Allorganization
Senator Kirsten Gillibrand (D-NY)individual
Maine Attorney General Aaron Freyindividual
U.S. Rep. Jared Golden (D-ME-2)individual
Senator Catherine Cortez Masto (D-NV)individual
View Susan Collins's Full Profile →View David Costello's Full Profile →View Graham Platner's Full Profile →View Janet Mills's Full Profile →