SANFORD — Enthusiasm for longtime Maine lawmaker Troy Jackson dominated a meeting of Democrats gathered Sunday to select delegates who later this week will pick the party’s replacement for former U.S. Senate nominee Graham Platner.

The York County meeting was the largest county caucus being held in the state Sunday, with 84 delegates to next weekend’s party convention at stake. While the delegates are not officially pledged to any candidate, at least 83 of the 84 elected said ahead of time that they plan to support Jackson, according to a list of delegates released by Jackson’s campaign — making it look increasingly likely he will be the party’s new nominee.

A total of 601 delegates, made up of 101 members of the Democratic party’s state committee and 500 representatives chosen at county caucuses, will select the party’s Senate candidate at the convention Saturday.

Following a strong performance at county caucuses this past Saturday, Jackson appeared poised to secure the nomination. Of the 319 delegates elected in eight counties by Saturday evening, 100, or about 31%, had publicly disclosed their support for Jackson. The candidate claimed to have secured delegate slates full of loyalists in several counties, including Cumberland and its 149 representatives to the convention.

One of his top rivals, Secretary of State Shenna Bellows, announced late Sunday morning she would withdraw from the race.

Hours earlier, Jackson rallied with supporters outside the Sanford Performing Arts Center, speaking to a small crowd who had gathered ahead of the start of the caucus meeting. Wearing blue jeans and a t-shirt that read “solidarity,” in a nod to labor groups, Jackson projected confidence while noting that he wasn’t taking his early lead for granted.

“Those delegates were not handed to us,” he said. “We earned them because hundreds and hundreds of people organized their neighbors, made the calls and showed up.”

Supporters holding “Troy Jackson” signs sat on the back of a pickup truck in front of where he delivered a 15-minute speech. Jackson talked about his roots as a logger from rural Allagash, in Maine’s northernmost county, his 20-year career in the Legislature and his goals of lowering the cost of living and making healthcare accessible for all.

He also hit Republican Sen. Susan Collins for her votes to confirm Brett Kavanaugh to the U.S. Supreme Court and for “standing by while the (Trump) administration attacked federal workers, unions, immigrants, healthcare and the basic rights of Maine people.”

Jackson did not name Platner, but pitched himself as a candidate who can carry forward Platner’s willingness to fight for everyday people.

“This moment, I know for a fact, is bigger than any one candidate,” Jackson said.

Inside the caucus, hundreds of would-be-delegates and participants mingled with each other and the Senate candidates. Nearly a dozen candidates are seeking the Senate nomination, and those present Sunday included former congressional staffer Jordan Wood and Maine Beer Co. co-founder Dan Kleban. But most attendees seemed to be siding with Jackson.

Leah Ingram, a Jackson supporter from Kennebunk, was seeking a spot as a delegate. Ingram, 60, said she would vote for Jackson if elected even though she didn’t appear on the “slate” of committed delegates his campaign released ahead of time.

Ingram, a writer and author, said she likes that Jackson is a “regular person” and that he was endorsed by U.S. Sen. Bernie Sanders, a progressive from Vermont. She also said she sees Jackson as the candidate best poised to unite voters in both northern and southern Maine.

“It’s like two different worlds, and I feel like if there’s anybody who can bridge the gap, and get independents and possibly Republicans to vote for them, I think it’s Troy,” she said.

Dozens of attendees at the meeting sported navy blue Jackson t-shirts, though there also appeared to be a large contingency of Nirav Shah supporters in green.

Jim Krzywicki, a Shah supporter who was running to be a delegate, said he likes that the former director of the Maine Center for Disease Control and Prevention is a “serious person” who has the integrity, education and understanding of complex issues to be a good senator. “He’s the real deal,” said Krzywicki, 74.

Sunday’s meeting was bustling from the start, as attendees crowded the arts center and mingled with one another prior to the start of the meeting. Voting was conducted online via participants’ cell phones or iPads, and was also open to people participating from home.

By 1 p.m. — two hours after the start of the meeting — attendance had dwindled to a few dozen as the last votes came in. York County Democratic Committee Chair Kathie Purdy, who led the meeting, joked with those remaining that if the process needs to happen next year she would be sure to have food trucks outside.

A little while later, the theme song from Jeopardy! played over the sound system. As the names of all 84 delegates and 17 alternates were read aloud, the auditorium filled with cheers.

While some attendees were likely disappointed that their preferred candidate hadn’t secured more loyal delegates Sunday, they said they are prepared to support whomever the party ends up picking.

“I think anybody with half a brain will support the Democratic candidate and get Susan Collins out of there,” Krzywicki said .