It says a lot about the state of disunity in the Republican Party that the speaker of the House, upon whom a goodly share of his party's hopes rest, is facing a genuine challenge in Tuesday's GOP primary.

I'm not talking about the U.S. House and Paul Ryan — though Donald Trump's "just not quite there yet" non-endorsement of Ryan last week put Wisconsin's imminent primary on journalists' radars.

Rather, I'm looking at the speaker of the Minnesota House, Kurt Daudt —and, while I'm at it, three other Republican legislators in and around the northern Twin Cities exurbs who are confronting intraparty challengers on Tuesday, mostly from the ideological right.

Republican legislative primaries are rare in most of Minnesota. Not so in the region just north of the seven-county Mosquito Control District. It's buzzing (I couldn't resist) about these contests on Tuesday's ballot:

• Daudt is paired in District 31A with business consultant and constitutional purist Alan Duff of Isanti, with whom he once served — and occasionally clashed — on the Isanti County Board.

• In adjacent District 31B, 10-term Rep. Tom Hackbarth is up against East Bethel businessman Cal Bahr, who needed only two ballots to wrest GOP endorsement from Hackbarth in April.

• In Senate District 32, State Sen. Sean Nienow faces Mark Koran of North Branch, a specialist in financial data management. A first-time candidate, Koran handily took the GOP endorsement from Nienow with an argument that a personal business bankruptcy involving a federal Small Business Administration loan makes Nienow unelectable.

• Farther northwest in District 15A, nine-term, GOP-endorsed Rep. Sondra Erickson is challenged by first-time candidate Tom Heinks of Princeton, a big fan of term limits.

It's tempting to tie this outbreak of intraparty dissention to Donald Trump, who last week seemed hellbent on fomenting division within the party that only a week earlier made him its presidential nominee. But what's happening in the northern exurbs is not a Trump-inspired phenomenon. Both Duff and Bahr are backed by the Tea Party Alliance, a group whose stirring predates the Orange One's presidential bid by several years. (Duff's ties to that group are close enough to be the subject of a complaint about illegal coordination filed last week with the state Campaign Finance Board.)

Yet the region's demographic profile suggests that it's fertile ground for Trumpism. Just 6 percent of the residents of Senate Districts 31 and 32 are nonwhite, the state Demograpic Center reports. Educational attainment in Chisago and Itasca counties is well below the statewide average. In both districts, median incomes are higher and poverty rates are lower than the statewide numbers, yet as of 2014, unemployment was also higher than the state average. That suggests that while most folks aren't struggling, they likely aren't feeling financially secure.

"It's a very blue-collar area," said former DFL state Rep. Jeremy Kalin, who represented Chisago County from 2007 to 2010 and now resides in Minneapolis. "A lot of the population are people who moved north from the Twin Cities and south from the Iron Range. They're folks who want to live where you can hop on your motorcycle or your snowmobile after work, where you're five minutes from your duck blind, where you can afford your own piece of the world and people aren't going to bother you."

That "don't bother me" spirit applies to government, District 31B candidate Bahr said. He described the region's political orientation as Republican with a strong strain of libertarianism.

"I just heard at someone's door the other day: 'Make sure we have cops, fix my roads and leave me alone,' " he said. Trump's presidential candidacy appeals to people who feel that way, Bahr said. "He's bringing people into the process who aren't satisfied with the way things are going."

The new Republican caucusgoers Trump attracted this year likely helped Bahr and Koran take party endorsement from Hackbarth and Nienow, respectively. And the same spirit that makes semirural life appealing probably contributes to a lack of deference to a political party's institutional norms, such as abiding by endorsements.

This year's intra-GOP tussles would be little more than a localized summer diversion were it not that one of them involves the second-most-powerful lawmaker in state government, the speaker of the House. And that his primary may be contributing to gridlock on the issue on which Minnesota most needs legislative action — transportation improvements.

It does so in two ways. One: It makes Daudt hyperattentive to local notions about transportation. The speaker's district is heavily populated by people who drive more than 30 miles to work each day. Many of those people moved to the northern exurbs when driving was cheap, and they want to keep it that way. Many see mass transit, especially light rail, as an expensive urban toy that somehow deprives them of better roads.

Two: It's hard to compromise with the DFL governor and Senate when your primary opponent and his friends are blasting you for so much as suggesting a teensy compromise proposal. That's what Duff is doing with Daudt's suggestion in May that if Republicans got their way on pretty much every other transportation fight, they might go along with an increase in highway-dedicated license tab fees.

That offer may still be on a table somewhere in the State Capitol complex. But Daudt hasn't mentioned it to Capitol reporters as the primary has drawn nigh, and I'll bet that's not a coincidence.

Minnesota's two big political parties should know the divided-government drill by now. The Legislature and governor's office have been in mixed hands for 24 of the past 26 years. Party folks ought to understand that legislative leaders must compromise with the other side for government to function.

When leaders make end-of-session deals, the purists at the grass roots are often disappointed. But unless they blunder badly, leaders should be able to count on their political parties to shield them from the purists' slings, arrows and primary challenges. When that does not happen, functional governance doesn't, either.

Lori Sturdevant, an editorial writer and columnist, is at lsturdevant@startribune.com.