VIRGINIA, Minn. — Rob Denne was raised as a Democrat.

"I grew up pretty poor. We were taught you're a Democrat if you're poor — you have to be because that's who's got your interest in mind," says Denne, on a blustery cold afternoon in this far north mining city of 8,700. He got the same message from his union leaders when he started working.

"I've changed all that," says Denne, 40, who drives a truck in the region's largest iron ore mine. Now, he looks for who will help his family, no matter their affiliation, he explains as he holds his daughter in one arm and her purple backpack in the other. "That's a common-sense thing. That doesn't make you a bad person."

So when Donald Trump vowed to put America First and slap protectionist barriers on rivals, Denne was part of a political shift in this region — a change that threatens one of the Democrats' last footholds in rural, white, working-class areas in the Midwest.

Republicans see Minnesota's Eighth District, which includes the state's vast mining range, as probably their best chance to gain a seat held by a Democrat next month and counterpunch losses elsewhere.

It's a different story 2½ hours south, where Republican incumbents in affluent suburbs are running for their political lives. West of Minneapolis, the Third District resembles many of the country's key swing seats, like those in Chester County and throughout New Jersey, where educated women are leading a Democratic surge that, they hope, changes power in the U.S. House.

Visits to the two districts last week provided a look at the geographic polarization that is shaping much of American politics, and has already split many states, including Pennsylvania, into deep blue pockets around cities, wide red swaths elsewhere, and little overlap.

If 2016 is repeated, Minnesota may not defy the trend much longer. Three rural seats held by Democrats shifted right, while two suburban seats held by Republicans slid left.

"There's going to be a rearrangement this fall," says Steven Schier, a retired political science professor from Carleton College, "and in future election years."

Eighth District: Duluth – Revived, Renewed

From his office in downtown Duluth, Don Ness looks out at the port that once made the city rich, and the aerial lift that towers above the water.

The port still ships grains from the Dakotas and taconite from the nearby mines, sent out to steelmaking centers such as Pittsburgh and Gary, Ind.

But these days, the port's main economic benefit isn't shipping, it's tourism, drawing visitors to see the 1,000-foot ships, sip at local breweries, and stroll its walkway along Lake Superior, says Ness, the mayor until 2016.

Don Ness, the former Democratic mayor of Duluth, Minn., speaks from his office in the city. Duluth is a liberal hub in Minnesota’s Eighth Congressional District, one of the most competitive in the country.
JONATHAN TAMARI / Staff
Don Ness, the former Democratic mayor of Duluth, Minn., speaks from his office in the city. Duluth is a liberal hub in Minnesota’s Eighth Congressional District, one of the most competitive in the country.

The revived city is a liberal hub in the largely white, rural Eighth Congressional District, a place of contrasts.

Sprawling across 27,900 square miles in Northern Minnesota, it's three times the size of New Jersey and includes sparsely populated rural stretches, lake communities that draw wealthy retirees, and growing exurbs north of Minneapolis. As Democrats have been chased out of similar working-class areas, such as Western Pennsylvania, they have held this district for 70 of the last 72 years, thanks to deep ties between the Democratic-Farmer-Labor (DFL) party and union miners who extract taconite from the nearby Iron Range.

Democrat Jim Oberstar held the seat for 36 years by combining conservative views on abortion and guns with labor support, says Ness, who worked for the congressman.

Those ties eroded as Democrats grew more uniformly liberal on social issues — but until Trump arrived, Republicans couldn't break through, "Trump has shown that he cares about their jobs," said state Senate Majority Leader Paul Gazelka, a Republican raised in the mining region.

Trump carried the district by 16 percentage points, after Barack Obama had won it by six.

That makes it the second-most Republican-leaning district still held by Democrats, according to the nonpartisan Cook Political Report.

In many ways, it has become a microcosm of a Midwestern swing state, as Democratic "purity tests" on cultural issues signaled to some voters that they no longer fit in party, spurring the kind of recent shift that happened years ago in other working-class areas, Ness says.

"There are very few states [where] Democrats are being competitive or winning largely rural congressional seats, but it happens in Minnesota because we have a tradition of progressive politics that matter and are still relevant in small towns," says Ness, 44. "Can we maintain that? I think that's what's in question."

Eighth District: Trump Country? Maybe.

Republicans and Democrats alike say the GOP nominee here, Pete Stauber, is a great candidate to take the open seat and turn it red.

He was a police officer in Duluth, a union leader, and now a St. Louis County commissioner. He won the college hockey national championship with Lake Superior State University in 1988 — handy in a district that houses the U.S. Hockey Hall of Fame.

Trump and Vice President Pence have campaigned in Duluth for Stauber, a fact he mentions early when speaking last Friday to students and staffers at Cromwell-Wright High School.

"We're blue collar, common sense conservatives, and we're getting moderate Democrats every day coming over to our camp because we have more in common than we have our differences," Stauber, 52, says in an interview.

Speaking to the class, he touts the economic gains under Trump and supports a controversial push to expand mining near the state's beloved boundary waters, "without having to look behind me to see if anyone's listening."

The idea, with echoes of Pennsylvania's fracking debate, has strong support from Republicans and many miners, but has left Democrats and others torn between the potential economic benefits and environmental impact.

"The reason we have the best beer in the Midwest is because we have the cleanest water. … I just don't want to see that reversed," said James Johnson, a 52-year-old server in Duluth's bustling restaurant scene. "You take our tourism away, and you take all our money away."

Stauber's opponent, DFL nominee and former State Rep. Joe Radinovich, has tried to walk a moderate line on mining and has won an endorsement from the United Steelworkers. His campaign did not make him available for interviews.

The race was trending in Stauber's direction. A New York Times/Sienna College Poll released in early September found a virtual tie, but a more recent survey had Stauber ahead by 15.

Third District: A push for a suburban wave

If Trump has fueled Republican hopes up north, he has the party worried in such suburbs as the Third District.

Just west of the Twin Cities, its towns mirror the Main Line: big houses, luxury cars, and white-collar workers. The district's 1.9 percent unemployment rate is the lowest of any congressional district, says Rep. Erik Paulsen, the incumbent Republican.

Hillary Clinton won the district, which is usually a battleground, by nine percentage points. As in many suburbs, Trump's demeanor has brought a backlash, especially among women.

"He's destroyed a lot of the character of our country," says Mary Jaffray, a 62-year-old from Deephaven, Minn.

A few blocks away in tony Excelsior, Democrat Dean Phillips sits in a cozy cottage, his campaign headquarters staffed largely by older, first-time campaign volunteers. "There are a lot of people who have been trying to find a way to apply their anxiety in something meaningful and perhaps legacy making," Phillips says.

With long hair, chunky black glasses, and stylish winter boots, Phillips has the breezy air of a serial entrepreneur. He led his family's distilling business, helped found the gelato brand Talenti, and more recently launched a chain of upscale coffee shops.

"It's the need for a check and a balance," he says. "I believe the Constitution anticipated a president like Donald Trump, prepared us for it. But I don't believe the Constitution anticipated a Congress filled with so many who lack courage."

Dean Phillips, a Democratic challenger running for Congress in Minnesota’s Third Congressional District speaks to a reporter at his campaign headquarters in Excelsior, Minn. on Oct. 13, 2018.
JONATHAN TAMARI / Staff
Dean Phillips, a Democratic challenger running for Congress in Minnesota’s Third Congressional District speaks to a reporter at his campaign headquarters in Excelsior, Minn. on Oct. 13, 2018.

Upstairs, about 30 volunteers prepare to go knock on doors. Some, such as Tim Carroll, are past Paulsen voters. But the protectionism that has cheered miners has forced price increases for his company, which makes and distributes parts for ATVs, automobiles and tractors.

Carroll, 51, regularly switches his votes between the parties, and has never volunteered or donated to a campaign, but he gave the maximum allowed to Phillips.

In another suburb, Paulsen, takes the phrase "running for office" literally.

Wearing a fleece pullover and a ballcap touting the curling team of his alma mater, St. Olaf College, he breaks into dead runs between houses in leafy Eden Prairie and Maple Grove. "Hi, I'm Erik Paulsen, I'm running for Congress," he tells people who answer their doors, handing them a flyer. "Call if you have any questions." Then he's off.

U.S. Rep. Erik Paulsen (R., Minn.) speaks with Pam Myhra, a Republican candidate for state auditor, before he knocks on doors in Maple Grove, Minn., on Oct. 13. Paulsen faces a stiff challenge in the suburban Third Congressional District.
JONATHAN TAMARI / Staff
U.S. Rep. Erik Paulsen (R., Minn.) speaks with Pam Myhra, a Republican candidate for state auditor, before he knocks on doors in Maple Grove, Minn., on Oct. 13. Paulsen faces a stiff challenge in the suburban Third Congressional District.

While similarly situated Republicans around Philadelphia have retired, Paulsen is fighting a national tide, which makes him one of the most endangered GOP Congressman. Polls suggest he trails Phillips. He has tried to focus on parochial issues, skipped Trump's rallies in Minnesota and used his first TV ad to highlight his differences with the president on mining.

Voters here want officials "who are also willing to stand up to their party or the president no matter who that person is, when it's important to Minnesota," Paulsen says.

It seems to pay off with some.

Al Johnson, 60, is a Republican who says he grudgingly voted for Clinton, but still supports Paulsen. He points to the congressman's work to repeal a tax on medical-device companies, a major industry that employs his wife.

Johnson is the kind of voter Republicans will need in these kind of districts. The question is how many will separate GOP candidates from a president who overshadows so much.