US Senator Maine in Statewide, Maine

2026 Primary Election

• Susan M Collins — Incumbent US Senator in ME

  Susan Collins is the incumbent U.S. Senator for Maine, a Republican currently serving her fifth term since 1997. At 73, she chairs the powerful Senate Appropriations Committee. She has officially launched her re-election campaign for a sixth term in 2026, having long intended to run. Known as a centrist, she has historically overperformed in tough elections. Her policy focus includes healthcare, with legislation like the Medical Nutrition Therapy Act and bills regarding family caregivers and Medicare services. She aims to unite Americans and ensure Maine’s Senate seat remains in Republican hands, stating her commitment to serving the state and nation.

• David A Costello — Environmental policy consultant in Brunswick, ME

  David Costello, 65, is a Democratic candidate for U.S. Senate in Maine for the 2026 primary. Born in Bangor and raised in Old Town in a working-class family, he earned degrees from George Washington University and the London School of Economics. With over 30 years in senior government roles, including environmental policy consulting, Maryland state government, and USAID, he emphasizes his extensive experience. Costello is running to protect democracy, the environment, and the economy, and to ensure Mainers have access to education, housing, healthcare, and job skills. He supports aggressive climate action and aims to defeat incumbent Susan Collins, having previously run in 2024.

• Janet T Mills — Incumbent Governor in Augusta, ME

  Janet Mills, the two-term incumbent Governor of Maine, launched a bid for the U.S. Senate in October 2025, aiming to challenge Republican Senator Susan Collins in the 2026 election. A moderate Democrat, Mills previously served as state attorney general and district attorney, gaining national recognition for her principled stands. Her platform focused on economic issues, advocating for fair tax policies and affordable healthcare, criticizing current federal policies as favoring the wealthy. Recruited by national Democrats, she cited a need for change in Washington. However, Mills withdrew from the Democratic primary in April 2026, citing struggles to gain traction against other candidates.

• Graham C Platner — Oyster farmer in Sullivan, ME

  Graham C Platner, born in 1984 in Maine, is an oyster farmer, Marine Corps and Army National Guard veteran who served multiple tours in Iraq and Afghanistan. A former defense contractor, he also serves as Sullivan's harbormaster and planning board chair. Platner is a Democratic candidate for the 2026 U.S. Senate primary, advocating for economic equality, universal healthcare, and environmental protection. He aims to offer a "better politics," despite past controversies regarding social media and a tattoo, and is challenging Governor Janet Mills for the nomination.