Bangor, Maine – A protester interrupted the final debate between Republican Sen. Susan Collins and Democratic challenger Troy Jackson in Maine, triggering a heated exchange after Collins suggested the demonstrator was a Jackson supporter.

The interruption came amid a debate that saw the candidates trade fire over numerous issues. The race between Jackson and Collins, who is seeking a sixth term representing the blue-leaning Northern New England state, is a top flip opportunity for Democrats as they try to win back the Senate majority from Republicans in the midterm elections.

The latest public opinion polls indicate a race within the margin of error between Collins and Jackson, a one-time logger and former state Senate president. The latest Fox News Power Rankings rates the race as a toss-up, as do leading nonpartisan political handicappers the Cook Political Report, Inside Elections, and Sabato's Crystal Ball.

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Republican Sen. Susan Collins of Maine and Democratic challenger Troy Jackson face off in their fourth and final debate Oct. 15, 2026, in Bangor, Maine (Paul Steinhauser/Fox News )

The protester, who interrupted Collins as she spoke, yelled out, "I'm terrified. AI data centers are destroying our climate. They are poisoning our water."

As security escorted the protester out of the debate hall, Collins suggested the man was a Jackson supporter.

"So this is obviously one of Troy's supporters," Collins said.

Jackson quickly fired back: "Oh, shut up, I did not — I didn't, I don't even know who that kid."

Another heated moment came a few minutes later, when each candidate was able to ask a question of the other.

Jackson, who grew up in rural northern Maine in the same county as Collins, asked, "What I'm curious about — is it just me that you look down on, or is it working class people overall?"

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Troy Jackson speaks after he became the Maine Democratic Party's choice to be its U.S. Senate nominee to replace Graham Platner on the ballot in November July 25, 2026, in Bangor, Maine. (Joe Raedle/Getty Images)

The senator shot back, "Troy, I do not look down on you or on anyone. I grew up in Caribou. My first job was picking potatoes."

As he works to oust Collins from the Senate, Jackson has repeatedly tried to anchor the senator to President Donald Trump, who has seen his approval ratings in Maine and across the country drop further underwater.

"The reality is a 100% of the time when Donald Trump needs her, Susan Collins is going to be there," Jackson claimed.

But Collins pointed to what she described as a "major difference between Troy and me. I vote very independently ... I am the most bipartisan member of the Senate."

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Republican Sen. Susan Collins of Maine is endorsed by the state chapter of the Fraternal Order of Police Oct. 14, 2026 in Bangor, Maine. (Paul Steinhauser/Fox News)

And referring to Jackson, Collins said, "We don’t need more people who are going to vote a straight party line."

Collins and Jackson spent much of the hour-long debate trading fire on issues including the Iran War, immigration, rising fuel prices and electricity rates, budget deficits, Supreme Court reform, dark money in politics, an assault weapons ban, and climate change.

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Campaign signs for Republican Sen. Susan Collins and Democratic challenger Troy Jackson in Bangor, Maine, Oct. 14, 2026. (Paul Steinhauser/Fox News)

Jackson won a special nominating convention in late July to claim the party's Senate nomination, which was left vacant after primary winner Graham Platner ended his campaign following allegations he raped a woman he previously dated. Platner denied the allegations but dropped out.

Jackson, who earlier this year unsuccessfully ran for the Democratic gubernatorial nomination, had campaigned alongside Platner during the primary campaign.

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Collins, who is the only GOP senator seeking re-election in a state Trump lost in the 2024 election, has a history of surviving Democratic efforts to unseat her.

Six years ago, she trailed Democratic challenger Sara Gideon, the then-Maine House speaker, but Collins won re-election by nearly nine points while former President Joe Biden carried the state by a similar margin.

Fox News' Jessica Sonkin contributed to this report.