In the end, life-long Democrat Andy Larson's decision to vote for Republican Stewart Mills over DFL incumbent Rick Nolan came down to the ads he's seeing every day on television.

"I'm very disappointed in my fellow party members in the types of advertisements just attacking Mr. Mills for his wealth," Larson said. "It's completely unwarranted. It's really turned me off."

As a persuadable voter, Larson, who voted for Nolan in 2012 and worked to elect him in the 1970s, is political gold in one of the country's most competitive U.S. House races.

Independent voters, another key group, are running two-to-one for Mills, a recent KSTP/SurveyUSA poll found. The same survey had Mills leading Nolan by 8 percentage points. National groups have the district pegged as a toss-up.

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• Poligraph: Anti-Nolan ad mixes truth, fiction in MN 8th

In a close race, the sliver of voters who waffle between parties could decide whether Nolan keeps his seat for two more years or whether Mills is sent to Washington.

In the final days of the election, they're being targeted like never before. Both sides have spent nearly $8 million combined on ads meant to bring out the party base and target swing voters.

MPR News tapped its Public Insight Network to find out what these voters think of the 8th District race in its final stretch.

Larson, who lives in Baxter, said there are other reasons he is siding with Mills this year. Chief among them is economic opportunity in an area Larson worries is losing its vitality. He said he's impressed by how Mills has grown the family business, Mills Fleet Farm.

"It's my view that a pretty astute businessman who's done a great job in growing the family business beyond what his father left him potentially can drive more growth and opportunity in Northern Minnesota than can additional federal involvement," Larson said.

That's one reason he's been so offended by Democratic Congressional Campaign Committee ads that target Mills for being too well-off for the district.

Paul Lemenager, a video producer in Duluth, feels the same way about the ads, which are coming from outside groups, not Nolan's campaign.

But he also says Mills' business experience is attractive.

"The fact that his family owns a business and understands what it takes to develop a business and jobs and to put a business into the black," Lemenager said. "Nolan has taken on the tone of a career politician. We have so much of that in Washington. We really need someone who understands what it takes to pull out of the slump economically."

John Reynolds, who lives in the Brainerd Lakes area, says he's voted for Republicans in the past, too but feels that Nolan better represents people like himself who are struggling to make ends meet.

To Reynolds, Mills represents privilege. He says Nolan is far more down to Earth, occasionally allowing Reynolds to trap muskrats on his property.

"I think that's really classy," Reynolds said. "I cannot see Mills doing that. You'd have to get by the fence and the guards (around his house). Mills doesn't have a clue as to what working class Minnesotans do."

Steve Wick of Duluth considers himself an independent voter, but of the liberal variety. He doesn't agree with Nolan on his views about mining, but he can't see himself voting for Mills, either, or the Green Party candidate Ray "Skip" Sandman.

"While some third party candidates would be fantastic, the likelihood of them winning in a close election year like this one forces my hand to vote for the candidate who will have the best opportunity to win but also represent most of my views," Wick said.

University of Minnesota political scientist Larry Jacobs said it's important not to read too much into Mills' lead among independents because many are right-leaning to begin with and ultimately side with conservative candidates. The bigger story, he added, is a candidate at odds with the shifting demographics of his district.

"Congressman Nolan is being hurt by his own unpopularity, and President Obama's unpopularity," Jacobs said, adding that the district is no longer a DFL stronghold. "It's a competitive district that's going to be a catfight (between the parties) every election."

Editor's note: An earlier version of this story stated that Steve Wick of Duluth disagreed with Nolan's views on health care. Wick does agree with Nolan on health care and the story has been updated to reflect that.