Maine Democrats are in uncharted territory.

On Monday, a woman who dated U.S. Senate candidate Graham Platner accused him of sexually assaulting her in 2021. Now, Platner’s supporters are reeling from the revelations as they try to square their support for the man and his ideas with the acts and behaviors he stands accused of.

“It just kind of confirmed what I had always suspected about him, about his treatment of women,” said Michael Bacon, 79, of Westbrook. “This certainly crosses the red line for me.”

“It actually makes me sick to my stomach,” said 47-year-old Natalie Krueger, of Sabattus. “He always seemed unstable. He’s not reliable.”

“I was hoping to believe him,” said Belgrade voter Joan Blethen, 76. “But now I can’t.”

The allegation published by Politico on Monday has created an extraordinary situation for Maine Democratic Party officials and voters alike.

Platner won the Democratic primary last month to become the party’s nominee to challenge Republican Sen. Susan Collins, a five-term incumbent, in the November general election. His populist messaging and unabashedly progressive positions resonated with voters looking for a fresh voice. Now, less than a month later, even Platner’s strongest supporters and closest allies are urging him to end his campaign.

“Everything to me feels like it’s upside down right now,” said 40-year-old Becky Johnson, a South Portland voter who had supported Platner since his campaign launched.

Johnson said as a Black Mainer, she watched as Platner reached out to communities of color in the state and built support within them in a way other candidates didn’t. Despite the calls from national and state leaders for Platner to withdraw, she said many of the supporters she’s spoken to within Maine are still behind him.

Johnson, however, and many other ardent Platner supporters are pulling back.

The latest allegation against Platner, who previously seemed impervious to an onslaught of controversies that dogged his campaign for months, has prompted a reckoning within the progressive wing of the Democratic Party that propelled his campaign to what initially seemed like an unlikely primary victory.

The 41-year-old oyster farmer had fended off scrutiny over a Nazi-linked tattoo on his chest, years of insensitive Reddit comments and allegations of extramarital sexting, among other scandals.

But the allegation from Jenny Racicot, a woman Platner dated for years, that he had drunkenly raped her in 2021 crossed a line for many of those who powered the Sullivan native’s unlikely ascent into the national political spotlight.

“I’m willing to forgive human frailty and some of the other accusations,” said Mark Siladi, a 65-year-old Democrat from Waterboro who had donated to Platner’s campaign. “But when someone undertakes or is accused of essentially rape, that puts them in the ‘no’ box for me.”

“It’s hugely disappointing for the Democrats,” Siladi added. “It’s just really deflating.”

Under Maine election law, Platner has until 5 p.m. Monday to withdraw his candidacy. If he does so, Democrats will have until July 27 to name a replacement.

But what that process would look like is anyone’s guess. Platner has yet to formally withdraw and Maine Democrats have never had to replace a statewide candidate this late in an election cycle.

Party officials across the state are stuck in limbo, uncertain about Platner’s future and how exactly they would go about replacing him.

Several leaders of county Democratic committees interviewed by the Portland Press Herald said they are weighing how to proceed with picking a new nominee should Platner drop out — though none would say whether they think Platner should drop his candidacy.

“The path forward is still being forged. But I am pushing behind the scenes for an open, fair and transparent process to get a new candidate,” said Greg Marley, chair of the Knox County Democratic Committee.

Many Democrats are calling for a speedy primary or caucus to decide a replacement for Platner. Nirav Shah, Maine’s former public health chief who lost his run for governor, said he wants a “transparent and open” process to find a new candidate. Joanne Mason, chair of the Kennebec County Democratic Committee, said the same.

Mason said she has seen past situations in which a nominee for a lower-ranking office was replaced, but nothing “at this level.”

“The Maine Democrats need to caucus, perhaps throughout each county, and take those caucuses’ results to the state committee, and the state committee should vote based on what their county had asked them to vote,” she said. That way, Mason added, “everyone can feel included in the decision.”

In a statement Monday, the state party pledged that the procedure will be “open, transparent and inclusive,” but stressed that nothing can happen unless Platner steps down.

“In no scenario is there a legal possibility for a nominee to be selected by an individual campaign,” the party wrote. “If the Platner campaign does not suspend by the 13th, there will be no option to select a new nominee.”

“The sooner this process can begin,” the statement continued, “The more time we will have to administer an intentional and inclusive process for Mainers and Democrats.”

Still, it will be an uphill battle for anyone who replaces Platner. Not only will they be campaigning on an expedited timeline, they will likely have to carry at least a portion of the baggage Platner brought to the race. National Democrats may also be reluctant to throw their campaign funds into an uncertain race against a well-funded, established Republican incumbent.

“I want to see how they recover from this,” said Peter Danforth, a 63-year-old independent voter from Auburn. “If they do it right, yeah, maybe, maybe I can lean more Democrat than Republican.”