– When a battle for a congressional seat becomes as taut as the one between Democratic Rep. Rick Nolan and GOP challenger Stewart Mills, campaigns start behaving frantically. Candidates drive hundreds of miles a day, squeezing in a coffee with a veterans group, in between picking up a national surrogate at the airport and dropping into call centers to thank volunteers, with the occasional hug for the random stranger who just picked up a yard sign.

Here in the Eighth Congressional District, whose geography and politics straddle Canadian boundary waters, blue-collar union miners, the artsy funky class of Duluth and the conservative exurbs of North Branch, the fight between Mills and Nolan has become one of the most closely watched House contests not just in the state, but the nation.

The district now ranks second among all U.S. House races for outside cash pouring in, according to the Center for Responsive Politics. A recent Star Tribune analysis showed that independent groups have pumped more than $12 million into ads, mailers and other efforts to influence the outcome.

The nation’s top politicos have beaten a path to northern Minnesota, with Vice President Joe Biden praising Nolan’s leadership at a rally in Hibbing last week. On Friday, National Republican Congressional Committee Chair Rep. Greg Walden turned up in this dusty industrial suburb of Duluth to thank Mills supporters.

Once a DFL stronghold, the Eighth has morphed into more of a swing district. Voters here bounced longtime Rep. Jim Oberstar in 2010, replacing him with Republican Chip Cravaack. That lasted two years, and in 2012 — a presidential year — voters swung back to the DFL, electing Nolan.

This time, every major national political forecaster is calling the race for the Eighth a tossup. Days ago, national political expert Larry Sabato at the University of Virginia went further, becoming the first to change the race to “lean Republican.”

A win for Republicans here would be a blow to Democrats, and strong GOP turnout could affect the races for governor, senator and control of the Minnesota House.

Ask the candidates why the race is among the country’s hairline fights, and they deliver starkly different answers. Nolan blames Green Party candidate Ray “Skip” Sandman for siphoning off 4 to 7 percent of the voters who otherwise might support him. Mills says the race isn’t that close, according to his own polls. He says he’s in a “battle with the couch” to turn out the Republican base.

“I’m very confident about what’s going to happen on Tuesday,” Mills said in an interview from his campaign office here. “But not cocky.”

The very nature of a race with such tight poll numbers means it was almost bound to turn sour.

Ads from national Democrats portray Mills as a fussy rich guy who eats lobster on yachts and is out of touch with the solidly middle class people of a district where the median income hovers just below $50,000.

“The Democrats have put a lot of money in picking on me for my hair and turning my family’s successful business into a negative or a bad thing,” said Mills, who sports shoulder-length locks. “Even though no one has been stung by this more than me, we still have the First Amendment.” Mills’ family owns the Mills Fleet Farm stores in the Upper Midwest.

Republicans call Nolan a liberal who stands too close to an increasingly unpopular president. They frequently tout Nolan’s F-rating from the National Rifle Association, calling him unfriendly to hunting, a sacrosanct ritual here.

Nolan’s staffers are quick to point out differences between the congressman and the president, but Nolan doesn’t tout that difference much on the stump, reverting to more liberal talking points, claiming Obamacare doesn’t go far enough (he prefers a single-payer system for all) and promoting gun control and background checks, calling the policies “reasonable.”

“It’s about living-wage jobs, it’s about health care, it’s about pensions, it’s about Social Security,” Nolan said. “That’s what joins us all together across the country, and it’s hard to be comfortable if you’re having to work two or three jobs to make a living.”

Those sentiments have resonated amid the deep-blue areas in the district’s northern stretches — all 19 Iron Range mayors collectively endorsed him earlier this week.

But the southern part of the district — whose population is growing at a much quicker clip — leans more conservative. Nine of the district’s southernmost counties supported the Republican gubernatorial candidate in 2010, the last midterm election, over Gov. Mark Dayton.

These voters are as detached from the Iron Range and Duluth as anyone in a Twin Cities suburb. They live amid outlet malls, Mills Fleet Farm stores, truck stops and Wal-Marts. Roughly half commute to the Twin Cities to work. Many of the others own small and medium-sized businesses or work in retail, according to census numbers.

Mills’ campaign has worked to lure those more exurban voters with positive messages about lowering taxes, easing environmental regulations and working on a plan to find more affordable health care. He is exceedingly careful not to trash Nolan too much in speeches and avoids generic-sounding talking points about House Minority Leader Nancy Pelosi.

“Mills comes from a family-run business, he knows these people,” said Bob Streater, a 60-year-old small business owner in Chisago County who supports Mills. “He’s in human resources. He knows the people he is paying. He knows their needs. He is a man of the people.”

Nolan says there isn’t a person in Congress who has worked harder than he has canvassing his district.

“I sense a lot of anxiety in being able to get health care and in being able to keep a job,” he said. The choice before voters, he said, is “Do you want to add more abundance of those who already have too much or do you want to try and make sure there’s enough for people who have too little?”

There’s another factor that makes the Eighth tough to predict. It is outperforming every other congressional district in the state in both mail and absentee voting, casting doubt on internal polls from both sides.

As of Thursday, 7.2 percent of registered voters had already requested absentee ballots. One nonprofit for the first time set up early and absentee voting stations on three of the state’s biggest Indian reservations in this district.

Tessa Hill, 69, lives in North Branch, where she and her husband own a business designing and manufacturing homes. Hill was deeply worried about the economy for a while. Everything slowed down when the unemployment rate jumped amid the country’s deep recession.

But, she notes everything is better now. She says she is supporting Nolan because he is sympathetic to small businesses and the environment — something she cares about.

“He’s not supporting the wealthy, the extremely wealthy,” she said. “He wants the majority, the middle class to be well taken care of. We’re working hard and it’s hard to survive. It’s difficult.”


Staff writers Rachel E. Stassen-Berger and Glenn Howatt contributed to this story.