AMNA NAWAZ: The list of Democrats calling for Maine Senate candidate Graham Platner to withdraw grew today after a woman he once dated accused him of sexual assault yesterday.

Independent Senator Bernie Sanders from Vermont, who backed Platner through earlier scandals, said he spoke to him today and -- quote - - "recommended that he step aside."

More than 30 Democratic senators have called for him to drop out, including Senate Minority Leader Chuck Schumer and Kirsten Gillibrand, who's in charge of electing Democrats to the Senate, as well as some influential Democrats outside of Congress, like New York Mayor Zohran Mamdani.

ZOHRAN MAMDANI (D), Mayor of New York City: I think the focus of today should be to respond to the gravity of what so many of us have read.

And I think that the only appropriate response is for the campaign to come to an end.

AMNA NAWAZ: Jenny Racicot said in interviews with Politico and CNN that Platner raped her nearly five years ago.

Platner denies the allegation.

He said yesterday he was reflecting on his path forward and has so far stayed silent today.

To discuss the future of the race, I'm joined now by Steve Mistler of Maine Public Radio.

Steve, thanks for joining us.

Let's just start with how this latest allegation is resonating in Maine and whether it's clear if Platner will heed those calls to step aside.

STEVE MISTLER, Maine Public Radio: Yes, well, he - - Platner has said that -- almost immediately after the publication of that Politico story that he's assessing his campaign, which is a sharp turn of where he's talked -- how he's responded to controversies in the past, where he's been pretty defiant that these are stories or allegations that have tried to just force him out of the race.

But this time there was an acknowledgement there that this is very damaging.

And you saw that, almost instantly, this sort of cascade of Democrats, national Democrats that you just referenced, abandoning their support of him and for and basically calling on him to get out of the race, and in Maine, where Democrats locally, and including some gubernatorial candidates who had sought his endorsement and in fact won it in some cases, were also calling for his -- for him to leave the race.

So this is a different type of scandal or different type of allegation, and I think this cratering of support is indicative of where probably where this is all headed for him.

AMNA NAWAZ: And, Steve, what's the timeline ahead?

If he does drop out, when does he have to do so by?

STEVE MISTLER: He needs to drop out by Monday the 13th by 5:00 p.m.

And that requires a formal notice to the secretary of state declaring that he's getting out of the race.

And if he does it by then, that would allow the Maine Democratic Party to basically nominate a replacement candidate.

And so there's this mad scramble under way to determine what that process looks like, because the Maine law is largely silent.

It kind of leaves it up to the political parties in these instances to determine how they want to field a replacement candidate.

So there's a lot of interest in how that's going to happen.

And, of course, the party has to do that by July 27.

So it's this very brief window, very reminiscent of when President Biden got out of the race and it was a very brief window to find a successor, and he ended up throwing his support behind Kamala Harris.

This is a very similar situation and probably giving some Democrats here a little bit of a flashback.

AMNA NAWAZ: And we're already seeing some folks raise their hand to say they would be considered possible contenders.

The former state CDC Director Nirav Shah, who ran for governor and lost, announced today he's considering entering the race.

Here's part of what he had to say.

NIRAV SHAH (D), Former Maine Gubernatorial Candidate: There are other candidates who might also get in.

What matters more than anything right now is that the process to select the nominee be as open and transparent as possible.

For example, there should be debates and town halls to make sure that Mainers know who they are selecting to take on Senator Collins.

AMNA NAWAZ: So, Steve, who are other likely contenders and what do you believe Maine Democrats will do to try to select whoever replaces Platner, if he does drop out, as expected?

STEVE MISTLER: Another name that's been mentioned is Troy Jackson.

He's the former Senate president.

He was endorsed by Bernie Sanders also and actually campaigned with Platner several times during the -- over the past nine months, maybe 10 months.

And I think there's some progressive activists, because Platner comes from that wing of the party as well, that would like to see Troy Jackson installed as a replacement candidate.

But there's a lot of other potential candidates that might want to run, including Secretary of State Shenna Bellows, who was in the gubernatorial primary and came in fourth in that contest.

She's expressed some interest in the race.

There's been several others as well.

I think the big question, though, is how the party goes and does this, because there's state committee, which is about 100 people.

It's really up to them to decide the process or to just pick the candidate themselves.

I think there's an interest in making that sure that this is a transparent process.

There's been discussions about having a caucus, basically redoing the primary, or even doing a state convention.

So a lot of speculation about what will happen, but I think transparency is a big issue for a lot of voters who turned out for Graham Platner on 9, and they want to have a transparent process that isn't just the party establishment picking a successor.

AMNA NAWAZ: All right, that is Steve Mistler of Maine Public Radio joining us tonight.

Steve, thank you so much.

STEVE MISTLER: My pleasure.