Graham Platner is officially the Democratic nominee in Maine to face Republican Sen. Susan Collins this fall, easily winning Tuesday’s primary to set up what’s expected to be among the most competitive Senate races of the year.

Platner was leading the primary field with 75 percent of the vote when The Associated Press called the race at 9:23 p.m. Eastern time.

Platner’s victory was expected after Gov. Janet Mills ended her campaign in late April, though her name remained on the ballot. But it was unclear what his margin of victory would be after his campaign was rocked by recent news reports that revealed extramarital sexual text messages and descriptions of emotionally volatile relationships with Platner by three former girlfriends.

Speaking at an election night party Tuesday, Platner, a military veteran and oyster farmer, indirectly addressed the news reports but also sought to shift the narrative to the grassroots anger that helped to fuel his political rise.

“If you believe, as I do, that we can change our politics and change our country, then you must also believe that people can change,” he said. “The reason I believe that is because I have lived it.”