The fourth and final debate in the Maine U.S. Senate race was a spirited affair that plowed some new ground, with Democrat Troy Jackson and Republican Susan Collins weighing in on gun control and the possible reform of the U.S. Supreme Court.

Thursday’s debate at the Gracie Theater at Husson University in Bangor was the only one to have a live audience, invited by the campaigns. It allowed for crowd reactions — and at one point an interruption by a protester — leading to a memorable exchange.

Jackson, a 58-year-old former logger, continued to tie Collins to President Donald Trump, whose actions and policies Jackson argued are driving up the prices of consumer goods, energy and fuel.

Collins, meanwhile, continued to focus on her seniority, which she says has brought $1.5 billion in federal earmarks to Maine in recent years. The 73-year-old has also sought to distance herself from Trump and shift blame onto Jackson for high energy prices, citing his votes in support of solar energy as Maine Senate president.

Here are the major takeaways from the final debate before the Nov. 3 election. It was conducted in partnership with Maine Public, the Portland Press Herald and NEWSCENTER Maine.

1. Protester interrupts, Jackson snaps

About 15 minutes into the debate, someone in the crowd stood up and began shouting about data centers. The moderator took a brief pause as security removed the young man, who appeared to be wearing a press badge.

“That’s obviously one of Troy’s supporters,” Collins quipped.

Jackson shot back.

“Oh shut up,” Jackson said. “I don’t even know that kid.”

Event organizers said the individual was not on the pre-registered media list, but presented a Bowdoin Orient press badge and was allowed in.

In an email Thursday night, the editor-in-chief of the Orient said the student paper did not send a reporter to the debate, and that the credential must have been fabricated.

2. Jackson stumbles on campaign finance

Collins and Jackson each had the opportunity to ask each other a question. And Collins appeared to get the best of both exchanges.

Collins called out Jackson for vowing not to take money from billionaires and corporate PACs. But she noted that Jackson’s campaign has been running joint ads with the Democratic Senatorial Campaign Committee, which she said received money from 28 billionaires and 190 corporate PACs.

Sen. Susan Collins directs a question to Troy Jackson during a debate at Husson University in Bangor on Thursday. (Gregory Rec/Staff Photographer)

Jackson appeared to have been caught off guard, at first confusing the joint ads, which contain his endorsement, with independent super PACs, which he cannot legally coordinate with.

Jackson, who earlier in the day announced he’d give away $15,000 in donations from oil and pharmaceutical lobbyists, also acknowledged that billionaires are supporting his campaign — a statement that drew a reaction from the audience.

“As far as billionaires that I might have on my campaign, that is accurate, but I haven’t made any deals like Sen. Collins has with those billionaires,” he said. “I don’t owe (them) my votes. I’m going to tax those billionaires when I get into the U.S. Senate.”

During his turn, Jackson brought up his working class roots and asked Collins if she looks down at him or all working people. Collins talked about how she started working in potato fields in Aroostook County at the age of 10.

“I do not look down on you or on anyone,” Collins said. “I have enormous respect for all the people of Maine.”

3. Supreme Court reform

The two candidates sparred over whether the U.S. Supreme Court needs reforming.

The Democrat said he supports term limits and enforceable ethics standards and would be open to adding members to the court, which he said is currently working for Trump and “the billionaire class.”

“It’s just gross the way that this has ended up,” Jackson said. “And we have to do something meaningful to actually give people’s confidence back.”

Troy Jackson answers a question during a debate with Sen. Susan Collins at Husson University in Bangor on Thursday.(Gregory Rec/Staff Photographer)

Collins disagreed. She said increasing the number of justices would go “completely against the vision of those who wrote the Constitution.” She stuck to her position when a moderator noted that the current number of nine justices was not in the Constitution.

“It’s inconsistent with the whole idea of the Supreme Court being insulated from politics,” Collins said. “That would make it a totally political body.”

Jackson, however, would get the last word.

“We have the best court that money can buy right now,” he said.

4. Through the looking glass on guns

A question about assault weapons produced some surprising answers.

Collins noted that she was a supporter of the original ban on assault weapons passed by Congress in the 90s. She accused Democrats of allowing that ban to expire because they wanted to expand it. And she said she voted to ban bump stocks, which increase the rate of fire in a weapon.

She said she supports “reasonable limits” on magazine capacity and would be open to increasing the age to legally obtain an assault weapon.

Jackson seemed more pro-gun by comparison.

“I’m not in favor of increasing the age,” he said. “It actually comes down to the person. I mean, we do have a culture here in Maine of people being able to buy guns.”

Jackson said he would not oppose an assault weapons ban, but he would oppose taking weapons away from people who already have them.

“I don’t see a good reason for assault weapons,” he said. “You can’t use them for hunting or anything like that. And so I would not be opposed to banning them.”