Senator Susan Collins of Maine may now be approaching her toughest re-election battle yet. The moderate Republican cast a critical “no” vote on Donald Trump’s massive domestic policy bill last week—legislation packed with tax cuts and rollbacks to safety net programs.

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In contrast, Democratic Governor Janet Mills remains significantly more popular and is increasingly seen as a potential challenger in 2026. Mills holds a net favorability rating of +10, with 51 percent of Mainers viewing her favorably and 41 percent unfavorably. Seven percent are neutral on Mills, and 1 percent say they don't know enough about her.