Democratic U.S. Senate candidate Graham Platner speaks during a primary election night watch party after winning the Democratic nomination in Blue Hill, Maine, on June 9, 2026. AP Photo/Robert F. Bukaty
National Democratic Party leaders threw their support behind Graham Platner within hours of his victory in Maine’s Democratic Senate primary on June 9, while the Republican Party’s Senate campaign arm released an attack ad on the same evening, opening up the general election showdown against incumbent Sen. Susan Collins (R-Maine) as Democrats seek to retake the upper chamber.
Platner, an oyster farmer and military veteran, easily won the primary, as his main rival, Gov. Janet Mills, had suspended her campaign in April but remained on the ballot. As of the morning of June 10, Platner was leading Mills by a margin of 71.8 percent to 19.5 percent, with other candidates falling farther behind.