Troy Jackson has defeated Republican incumbent Susan Collins for a U.S. Senate seat in Maine, dealing a significant blow to the Republican Party and handing Democrats a crucial victory in their push to reclaim the Senate majority.

The race was called by the Associated Press.

Collins, the longest-serving Republican woman in the Senate, had repeatedly defied national political trends to win in a state that consistently votes Democratic at the state level. That streak ended Tuesday night, bringing her nearly 30-year tenure in Congress to a close.

Jackson's win makes him the first Democrat to represent Maine in the Senate since 1995.

Jackson's path to the nomination was itself dramatic. A fifth-generation logger, he entered the race in August after replacing Graham Platner as the Democratic nominee. Platner had suspended his campaign following an allegation of rape, which he denies.

Jackson sought to maintain the momentum generated by Platner's antiestablishment, change-focused campaign. He ran on a progressive populist platform, emphasizing his working-class background and deep ties to the labor movement.

He also worked to link Collins to several Trump administration policies that have fueled economic anxiety in Maine, including rising oil and gas prices tied to the Iran war and financial strain on Maine businesses from trade tensions with Canada, which shares a border with the state.

Despite his late entry into the race, national polls showed Jackson and Collins in a virtual tie heading into election day.

The contest ranked among the most expensive Senate races of this year's midterms. Democratic- and Republican-aligned groups spent more than a quarter of a billion dollars on advertising, according to data from AdImpact.

Collins campaigned on her record as an independent voice in the Senate and touted her role as chair of the Senate Appropriations Committee, arguing the position had helped direct more federal funding to Maine.

Democrats sought to undercut that argument. Campaign ads repeatedly highlighted her 2018 vote to confirm Brett Kavanaugh to the Supreme Court, a vote that proved decisive in cementing a conservative majority that went on to eliminate the constitutional right to abortion in 2022. Collins has said she does not regret that vote and describes herself as a supporter of abortion protections.

In an October interview with Maine Public Radio, Jackson dismissed Collins' claims about delivering federal resources to the state.

"She's losing more money than she's bringing in. You know I keep saying, it would be great if she just stopped doing anything. We'd be better off," he said. "We're losing a lot more; our healthcare, Iran war, tariffs. I mean, all these things are costing the state way more money than Susan Collins can ever bring in."

An analysis by sources at a major U.S. newspaper found that Collins breaks with her party on Senate votes more than any other Republican. However, the same analysis found that the rate at which she does so has dropped considerably during President Trump's second term.

At the final Senate debate in October, Collins argued that moderate representation was a strength for Maine voters, not a weakness.

"[Jackson] is going to be an automatic vote for the Democratic position no matter what," she said. "We have lost a lot of the centrists, and one of the reasons is we need people who will work across party lines."