CHRIS HAYES, HOST: Tonight we have some breaking news surrounding Maine Democratic Senate candidate Graham Platner. New York Times has exclusive reporting tonight on three women who previously dated Platner and called his behavior in those relationships unsettling, volatile, and toxic. Graham Platner will be joining me in just a moment to address the allegations reported in that story.

Now, the report comes as Democrats are more aware than ever about how the effort to hold Trump accountable will, of course, require flipping seats in the currently Republican majority Senate. And lots of political observers agree that one of their best shots at flipping a seat should be in Maine. It's a state that Donald Trump actually lost three times. He lost it to Kamala Harris, Hillary Clinton, Joe Biden. It is represented by longtime Republican incumbent Susan Collins, who has held that seat since 1997, even as the state has elected Democrats at other statewide offices and for president.

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And it's also very clear that Platner is a very natural, high-level political talent. He's been able to draw large crowds throughout the state, sometimes in small towns where half the town's there. He has barnstormed basically nonstop doing event after event after event.

It's also true that Platner is a political unknown. He's a combat veteran who readily admits to have -- having a very messy past. And with that past has come a slow, consistent drip of negative headlines that he has had to reckon with since entering the race.