Troy Jackson, a former state lawmaker and logger, has secured the Democratic nomination for the U.S. Senate in Maine, setting the stage for a crucial November contest against long-serving Republican Senator Susan Collins.

The outcome of this race could prove pivotal in determining which party gains control of the Senate.

Mr Jackson's nomination follows the withdrawal of Graham Platner, who had initially won the Democratic primary in June. Mr Platner stepped down earlier this month amid an allegation of sexual assault, which he has denied.

His departure necessitated a swift and unprecedented process for Democrats to select a new candidate. Over 600 delegates from across Maine convened in Bangor, approximately 130 miles north of Portland, to cast their votes for a replacement nominee.

Mr Jackson ultimately secured the support of a majority of these delegates, clinching the nomination. His victory was widely anticipated, with his campaign having previously indicated that more than 480 delegates had pledged their vote to him.

A progressive figure, Mr Jackson advocates for policies such as Medicare for All and the dismantling of Immigration and Customs Enforcement.

Jackson first ran for office as a Republican in 2000 when he sought a seat inside Maine’s House of Representatives. He lost, but won two years later when he ran as an independent. He switched to the Democratic Party in 2004, and eventually became the Maine Senate president before leaving the statehouse in 2024.

He came in third while running for governor in this year’s Democratic primary election, but had the backing of Platner, U.S. Sen. Bernie Sanders and Our Revolution, the political organization founded by Sanders.

Support coalesced around Jackson - a fifth-generation logger from rural northern Maine who campaigned alongside Platner during a failed bid for governor and was a favorite among progressives to replace him.

“When the people in power refuse to listen, you have to organize, you have to stand in solidarity, together. And you have to make them listen,” Jackson said during a speech at a last-minute nominating convention held Saturday.

The Maine Democratic Party has been scrambling to choose a new nominee after Platner, who sailed to victory in the Democratic primary in June, was accused by a former girlfriend of sexually assaulting her in 2021.

Platner denies the allegation, but quit the race after key supporters called on him to withdraw.

Democrats have seen Maine as the party’s best opportunity to flip a Senate seat this year because it is a competitive Senate race in a state that President Donald Trump lost in 2024. But defeating Collins won't be easy. The five-term incumbent holds a fundraising advantage, while the new nominee will have less than four months to sell themselves to voters.

Maine law gave the state party authority to choose a replacement and required a new nominee to be named by Monday — 99 days before the Nov. 3 election.

Maine Democrats' never-before-used process of voting on a new nominee involved more than 600 Democratic delegates gathering in Bangor, about 130 miles (209.21 kilometers) north of Portland. The delegates were elected at county party meetings last weekend.

Once Platner dropped out on July 10, a flood of former governor candidates — including Jackson — and others jumped to try to take Platner's place. But by July 19, most had abandoned their bids, with Jackson emerging as the clear favorite.