Democrat Troy Jackson defeated longtime Sen. Susan Collins Tuesday in Maine’s midterm Senate election, ending the incumbent’s nearly 30-year-long run in the upper chamber.

The victory for the second-choice candidate hands Democrats a critical election night win in one of the most closely watched Senate races of the cycle, and marks a blow to Republicans battling to keep their slim majority in the upper chamber. 

Jackson garnered 52.7% of the vote, compared to Collins’ 47.2%, with about two-thirds of the ballots tallied.

It’s a remarkable turnaround for Jackson, the third-place finisher in the Maine Democratic primary for governor, who was swapped in at the last minute after the campaign imploded for the original Senate nominee, Graham Platner.

Collins, 73, will leave Congress as the longest-serving female Republican senator in history. 

“It has been the honor of my life to serve the people of Maine in the United States Senate. I’m proud of all I have been able to accomplish for our state and for our country in the past 30 years,” Collins said.

The senator, known for her history of pulling off upset wins in the blue-leaning state that has never gone for President Trump in a presidential election, was the last remaining congressional Republican from New England.

Trump loomed large over the race in the Pine Tree State. 

Collins frequently emphasized her willingness to defy the president, along with her 30 years in the Senate and record of bipartisanship, as crucial for getting things done for Mainers.  

The dean of Maine’s congressional delegation, Collins described herself as “not exactly [Trump’s] favorite senator” in her first debate against Jackson and nudged the president away from stumping for her in the state. 

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On the campaign trail, Collins repeatedly distanced herself from several Trump policies, including the war in Iran, the trade war with Canada and the One Big Beautiful Bill Act.

Meanwhile, Jackson argued that her votes, including her support for Supreme Court Justice Brett Kavanaugh in 2018, have enabled Trump’s agenda. 

Kavanaugh sided with the majority of justices in the landmark 2022 case that overturned Roe v. Wade, and the pro-choice incumbent’s vote to confirm Kavanaugh became a major focus of Democratic attack ads against Collins. 

Jackson, a fifth-generation logger, ex-Republican and former state Senate president, replaced Democratic primary winner Platner on the ballot in July after the disgraced first pick was accused of rape. 

Platner withdrew from the race on July 10, days after a woman he previously dated, Jenny Racicot, publicly alleged that he drunkenly raped her at her Maine home in 2021.

Platner’s exit set off a mad scramble for the state Democratic Party to find a replacement, and the vast majority of state party delegates rallied around Jackson by July 25. 

Jackson finished third in the Democratic gubernatorial primary just a few months before he was tapped for the Senate race. 

Socialist Sen. Bernie Sanders (I-Vt.) and “Squad” Rep. Alexandria Ocasio-Cortez (D-NY) were among the lefty lawmakers that endorsed Jackson in his race against Collins. 

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For her part, Collins enlisted former Sen. Joe Manchin (I-W.Va.) to campaign with her in the final weeks of the race. 

Manchin, a Democrat-turned-independent, praised the five-term Republican as “the soul of the Senate.” 

With nearly $200 million spent on campaign ads, the Maine race was the most expensive per capita, according to an Axios analysis of AdImpact data. 

Republicans spent an estimated $96.99 per voting-age resident, while Democrats spent $69.52.