


Primary Election
Party selects its nominee.
Current roleGovernment/public-sector administrator
PartyDemocratic
Political ideologyProgressive Democrat
LocationMaine
BackgroundGovernment/public-sector administrator
EducationOld Town High School (graduate)
Notable personal detailsDavid Allen Costello is a Democratic candidate for U.S. Senate in Maine. He has worked in senior-level government and public-sector roles, including with USAID and in Maryland state government. He is a graduate of The George Washington University (B.A. in Political Science and History) and the London School of Economics (M.S. in Government/Political Sociology). He is based in Brunswick, Maine.
Supports increasing taxes on wealthy individuals and corporations, expanding tax credits and incentives for low- and middle-income people and small businesses, and using tax changes to fund expanded government programs and investments (infrastructure, R&D, housing, Social Security/Medicare protection). Advocates a global minimum corporate tax and reallocating subsidies from large agribusiness and fossil fuels to rural and clean-energy initiatives.
Supports expanding access to government-provided coverage by offering Medicare (including dental and vision) to anyone who wants it, improving the Affordable Care Act for those who do not enroll in Medicare, and increasing funding for substance use and mental health services.
Supports comprehensive immigration reform that secures borders while facilitating legal immigration and addressing worker shortages; emphasizes enactment of reforms to expand legal pathways alongside border security measures.
Supports protecting women’s reproductive rights, including codifying Roe v. Wade and increasing funding for organizations like Planned Parenthood. Backs actions to protect reproductive health decisions and broader civil rights protections.
Supports an aggressive, science-based national climate action plan with strict greenhouse gas emissions caps, large clean energy and efficiency investments, GHG sequestration goals, and reallocation of fossil-fuel subsidies toward clean energy. Backs policies such as a carbon tax and expanded renewable development (wind, solar, hydro) while urging protections for affected communities and fisheries.
The candidate supports stronger federal gun safety laws including universal background checks, safe storage requirements, bans on military-style/assault weapons, red flag measures, and increased funding for mental health and community policing; he also supports stricter sentencing for gun-related crimes while saying he would not deny responsible citizens the right to own guns.
David Allen Costello is one of the Democrats competing in Maine’s crowded 2026 Senate primary, which is now focused on choosing a replacement nominee after Graham Platner withdrew. The party is set to pick its nominee at a July 25 convention, and candidates have already begun debating and positioning themselves for the race against Republican Sen. Susan Collins. Costello has also been noted for highlighting endorsements from lobbyists as he campaigns.



Aggregation source: FiftyPlusOne
Endorsers of David Allen Costello for Maine Democratic Senate nominee?
Public endorsement
Gov. Janet Mills endorsed David Costello in Maine's U.S. Senate race.
2024
2026
LatestCycle 2024
Cycle 2026
Source: FEC