Republican Pete Stauber leads over Joe Radinovich, right, in what’s been a reliably Democratic congressional district for decades. (The Minnesota Star Tribune)

Recent public polling by NBC News and the Star Tribune/MPR News suggests Democrats are going into the stretch run of the election season in relatively strong position, with one big exception — the Eighth Congressional District.

A New York Times poll showed Republican Pete Stauber with a 15-point lead over Democrat Joe Radinovich in a northeastern Minnesota district that has been one of the most reliably Democratic districts in the country for nearly a century.

The Radinovich campaign disputes the poll findings.

"No one who understands this district takes that poll seriously," said Bennett Smith, a Radinovich spokesman. He noted that a Times poll taken just a month before had Radinovich narrowly ahead, adding, "I mean, the electorate they created, the turnout numbers, and the methods are literally imaginary."

But on two other fronts, signs pointed to Stauber taking a commanding position. The Democrats' Washington-based congressional campaign arm appears to have retreated from the Eighth to put resources into other Minnesota races, leaving Radinovich to fend for himself. And the respected, nonpartisan handicapper, the Cook Political Report, moved the race from "tossup" into "lean Republican."

So what's going on in the Eighth?

No doubt Stauber's profile — a hockey player and retired police officer who is married to a veteran — is helping Republicans. And they've been pounding on Radinovich for driving infractions and a long-ago arrest for drug paraphernalia (he was 18).

But the change in the Eighth is also structural. Rural regions where the DFL was once strong are moving rapidly into the Republican column. This trend is newer to Minnesota but has been an established fact in the rest of the country for two decades.

In the Eighth, the canary in the mine was President Donald Trump's crushing 15-point victory in 2016. He retained sky-high popularity in northern Minnesota in the Star Tribune's September poll.

As Republican-leaning elections analyst Henry Olsen wrote recently, we are seeing a "highly nationalized electorate that is deciding to support a party rather than a candidate and using Trump as a proxy for the Republican Party at large."

This meshes with the conclusion of Gary Jacobson, a University of California, San Diego political scientist who examines trends that "have gradually transformed midterm elections into highly nationalized, president-centered events."

Culturally, the Eighth has long held potential for Republicans given the party's more conservative positions on guns and social issues. Trump's support for steel tariffs will cement his — and, thus, the GOP's — position even more in a district that includes the Iron Range.

After a century with the Democrats, a New York real estate maven could be the man to put the Eighth into the GOP column for a long time to come.

Joe Radinovich, Pete Stauber’s Democratic challenger, at a parade in Chisago, Minn., Aug. 17, 2018. Progressives and environmentalists in the Twin Cities are at odds with farmers and miners, many of whom feel the Democratic Farmer Labor Party has left them behind. (Tim Gruber/The New York Times) (The Minnesota Star Tribune)