Former Maine Senate President Troy Jackson moved Tuesday to form a exploratory committee that would position him to potentially replace Graham Platner as the Democratic candidate for the U.S. Senate on the November ballot.

Tuesday’s filing with the Federal Election Commission listed the formation of a “Troy Jackson Senate Exploratory Committee.” It allows the Allagash Democrat to begin raising money without formally declaring his candidacy. A “Draft Troy” movement featuring a website also popped up this week to back Jackson as the new Senate nominee.

Democrats at the state and national levels have called on Platner to step aside as the party’s nominee to face U.S. Sen. Susan Collins, R-Maine, after Politico reported Monday that a woman accused Platner of sexually assaulting her in 2021. Platner and his campaign denied the allegation, and the candidate had not dropped out as of Tuesday afternoon. He has until 5 p.m. Monday to do so.

Jackson, 58, who finished third in last month’s gubernatorial primary, said in a Tuesday evening statement announcing the exploratory committee that he is weighing his options.

“To all of you who have poured your passion, dedication, and hope into this movement, I know you are hurting, and I want you to know that your efforts were not in vain. Your contributions matter. Your time matters. You matter,” Jackson said. “Together, we can bring our shared progressive vision to life. We can pass Medicare For All. We can take on corporate power. We can create the future Mainers and Americans deserve. And we can unseat Susan Collins once and for all.”

Jackson added that although he has “not made any final decisions yet, I’m deeply humbled by the outpouring of support and encouragement I’ve received.”

The Bangor Daily News first reported on Jackson’s filing.

Jackson is the first Democrat to formally file exploratory paperwork, though others who lost last month’s primaries for governor and the 2nd Congressional District — including former Maine Center for Disease Control and Prevention leader Nirav Shah and former Capitol Hill staffer Jordan Wood — said Tuesday they are considering bids should Platner end his campaign.

Platner, 41, enjoyed a meteoric rise after entering the race last August. He posted strong fundraising numbers and drew large crowds at rallies, pushed past various controversies in the past few months and brushed aside Gov. Janet Mills and others to easily win the Democratic primary.

But the sexual assault claim swiftly changed everything, with most of Platner’s supporters at the state and national levels now calling for him to drop out.

Jackson, a logger from Aroostook County, first ran for the Legislature as a Republican in 2000 before becoming an independent and winning election to the Maine House of Representatives in 2002. He joined the Democratic Party before the 2004 election and beat Republican opponents in both chambers over the years to represent a remote part of the state that turned increasingly red.

Platner said earlier this year that he marked Jackson first on his Democratic gubernatorial primary ballot. The Senate candidate said he also ranked the eventual gubernatorial nominee, former Maine House Speaker Hannah Pingree, and Secretary of State Shenna Bellows.

Jackson has enjoyed strong support from labor unions and from U.S. Sen. Bernie Sanders, I-Vermont, who had also endorsed Platner before withdrawing that support Tuesday. Jackson, Platner and Sanders appeared at multiple rallies together, most recently at Orono and Portland events in May.

If Jackson were to become the Senate nominee, Republican groups will almost certainly highlight those appearances in attack ads to link Jackson to Platner.

Our Revolution, a progressive political action committee that grew as a continuation of Sanders’ 2016 presidential campaign, said Tuesday it is backing Jackson to replace Platner on the ballot.

Jackson joined other Democrats in shifting from supporting Platner to calling on him to withdraw from the race, saying in a Monday statement there “is no place in our politics for sexual violence.”

“This is not what we stand for. Not as Democrats, not as Mainers, not as human beings,” Jackson said. “For too long, women who survive sexual violence have been told to stay quiet, to protect the men who hurt them, to think about the campaign, the party, the cause. We cannot ask women to trust us with their futures while looking the other way when one of our own hurts them. That ends here.”

If Platner ends his Senate campaign, the Maine Democratic Party has until July 27 to pick his replacement. Party officials are discussing what the next steps could look like, but it’s unclear how the process will shake out.