Graham Platner on Tuesday officially became the Democratic Party’s nominee to take on GOP Sen. Susan Collins in Maine in one of the nation’s most high-profile Senate races. The political newcomer easily won his primary as the only serious Democratic candidate left on the ballot,

Liberal upstart Graham Platner won Maine’s Democratic Senate primary on Tuesday night, defeating Maine Gov. Janet Mills weeks after the more establishment-backed pick ended her campaign. The Associated Press called the race soon after polls in Maine closed at 8 p.

Democrats in Maine set aside the controversies surrounding political newcomer Graham Platner and selected him on Tuesday as their nominee to challenge GOP Sen. Susan Collins, the Associated Press said,

Graham Platner remains the candidate expected to win the Democratic Senate primary in Maine, but voters have mixed views about his viability going forward. CNN’s Arlette Saenz spoke with some of those voters.

Platner defeated Gov. Janet Mills and professor David Costello to win the nomination. Platner, a progressive, launched to fame last summer with a viral launch video promising to take on the “oligarchy” and has run hard against President Donald Trump’s war with Iran.

Graham Platner faces controversies in Maine's Democratic Senate primary as Trump's endorsement power is tested in South Carolina's GOP gubernatorial race.

They’re ready to gamble on Graham Platner, flaws and all. Tuesday’s Maine Democratic Senate primary has emerged as an ideological proxy battle over the party’s future, with Platner’s string of escalating controversies at the center.

Democrats in Maine appear poised to officially choose Graham Platner as their nominee to take on Republican Susan Collins for her U.S. Senate seat. CBS News' Caitlin Huey-Burns and Robert Costa have more.