Maine Governor Janet Mills Runs for U.S. Senate Instead of Reelection

Maine Gov. Janet Mills, a Democrat, is running for the U.S. Senate in 2026 rather than seeking reelection as governor, setting up a general election matchup against Republican incumbent Sen. Susan Collins. This decision means Maine's governorship will be open in the 2026 election, one of 36 gubernatorial races taking place nationwide that year. The Senate race has been described as one of the more competitive and nationally watched contests of the 2026 election cycle. Mills' entry into the Senate race created a contested Democratic primary, with oyster farmer and military veteran Graham Platner also seeking the party's nomination. According to polling data cited by Morning Consult, Mills has the lowest approval rating among Democratic governors nationwide as of April 2026. Despite this standing, the same reporting indicates Mills remains more popular among Maine voters than Collins, her prospective general-election opponent. As of the most recent reporting in July 2026, the Democratic primary between Mills and Platner had not yet been resolved, and the eventual Democratic nominee to face Collins remained undetermined. The full field of candidates for Maine's open governorship, to be vacated by Mills, was not detailed in available reporting. Specific approval rating figures and polling methodology behind the 'most unpopular' characterization were not provided in the excerpted material.