Graham Platner wins Maine Democratic Senate primary, targets Susan Collins

Graham Platner seized the Democratic nomination for Maine’s U.S. Senate race and immediately turned his populist message toward Republican Sen. Susan Collins, setting up one of the most closely watched contests of the 2026 midterms. Early results showed Platner with about 72 percent of the vote, a decisive margin that came despite a rocky stretch in which recent scandals had become a major part of the campaign.

The June 9 primary left Collins facing a newly chosen Democratic opponent after running unopposed on the Republican side. Platner’s path ran through Janet Mills, the outgoing governor who suspended her campaign in April but stayed on the ballot and emerged as his main challenger. His victory suggested that Maine Democratic voters were willing to back a candidate with sharper outsider appeal even after a bruising race, a sign that the party’s appetite for establishment credentials may be weaker than its desire for a message aimed squarely at Collins.

That makes Maine more than a state-level result. Collins is the only Republican senator representing a state carried by Kamala Harris in 2024, which has made her seat one of Democrats’ clearest pickup opportunities. With control of the Senate on the line in November, the Maine race has become a test of whether a populist challenger can convert intraparty energy into a general-election coalition broad enough to unseat a long-serving incumbent.

The same day, South Carolina held statewide primaries for governor, U.S. Senate, U.S. House, attorney general and secretary of state, offering a second snapshot of party energy ahead of the fall campaign. The South Carolina Election Commission said more than 318,600 early ballots were cast in a record-breaking early voting period, underscoring how heavily both parties are leaning on turnout operations and early participation as they head toward November. The state had 3,395,961 registered voters at the time of the primary.

Taken together, the two states showed the shape of the coming fall fight. Maine handed Democrats a nominee who leaned into confrontation and anti-establishment politics, while South Carolina showed a Republican electorate already engaged across a crowded ballot. In a year when primary elections across all 50 states are serving as a test run for the general election, those signals may matter as much as the winners themselves.