Maine Governor Janet Mills Launches Bid to Unseat Sen. Susan Collins in High-Profile Democratic Primary

Strategic Insights -

Maine Governor Janet Mills (D) has formally launched her campaign to unseat Sen. Susan Collins (R-Maine), setting up a high-stakes primary battle between the establishment and populist factions of the Democratic Party. Mills, who has been endorsed by several prominent Democrats, including Sen. Catherine Cortez Masto (Nev) and EMILY's List President Jessica Mackler, is seen as a strong contender in the crowded primary field. However, progressive forces, including Sen. Bernie Sanders (I-Vt.), are backing oyster farmer and military veteran Graham Platner, who has gained traction with his focus on economic populism and his campaign's ability to rake in $4 million since its launch in August.

Key Takeaways:

  • Janet Mills, the incumbent Maine Governor, has launched her campaign to unseat Sen. Susan Collins in the high-profile Democratic primary.
  • Mills has been endorsed by several prominent Democrats, including Sen. Catherine Cortez Masto (Nev) and EMILY's List President Jessica Mackler.
  • Graham Platner, backed by Sen. Bernie Sanders, is another contender in the primary, focusing on economic populism and key issues facing working-class Mainers.
  • Platner's campaign has raised $4 million since its launch in August, indicating growing support among progressive and younger voters.
  • The primary has become a contest between establishment candidates, like Mills, and those pushing for change, like Platner.
  • Some Democrats view the primary as a test case for the party's direction, particularly in terms of age, working-class issues, and issues affecting young voters.
  • Senate Republicans welcome the primary, pointing out Mills's age and her record as governor, which they argue has led to a weakening economy in Maine.

Statistics:

  • Since launching his campaign in August, Graham Platner has raised $4 million.
  • Janet Mills has secured at least half of the vote in both of her gubernatorial wins.
  • EMILY's List President Jessica Mackler has endorsed Janet Mills, calling her a proven leader who will "fight Trump head-on."
  • Cook Political Report shifted its rating of the 2026 Senate race from "lean Republican" to "toss-up" after Mills announced her candidacy.
  • The Senate Democrats' campaign arm believes they can flip Collins's seat in 2026.

Sources:

  • Caroline Vakil, "Maine Governor Janet Mills announces 2026 Senate bid to unseat Susan Collins", The Hill
  • Source: Mills's campaign ad, citing her record in defending the state's policy on transgender girls in girls sports and standing up to Trump's threats to withhold federal funding.