Perhaps it is the long, lonely winters; perhaps it is the isolation of the great farms. Whatever the reason, Iowa is a state of profound quiet. The first time the Southern novelist Allan Gurganus went to a dinner party there, he grew uncomfortable at the long silences around the table — two minutes, then three, then four, when the only sound he heard was “fresh corn being masticated by molars around the room.”

And yet, in those silences in a state where Robert Frost said the rich soil “looks good enough to eat without putting it through vegetables,” deep mysteries fester, and bitter rebellions, too.

One of those mysteries, and one of those rebellions, is simmering right now as the midterm congressional elections approach.

It isn’t raucous like the Iowa City beer riots, an 1884 rebellion against a legislative diktat that banned the consumption of alcohol and prompted mobs, threats, the stripping and tarring of one city prosecutor, the stabbing of another and the pummeling of a judge. It isn’t violent like the 1931 farmer rebellion over a law requiring the testing of cows for tuberculosis, which set off a reaction requiring the dispatch of 31 Iowa National Guard units to quell the uproar. Nor does it match the upheaval a year later, when dairy farmers furious over low milk prices blockaded 10 highways leading into Sioux City, shut down creameries, picketed rail depots, and employed spiked planks and threshing machine belts to enforce their blockades.

This is merely a rebellion at the ballot box, and its effects may be far greater than any of the rural rebellions of the past.

In the four years between the two elections with Donald Trump on the ballot, voter participation in Poweshiek County, in the center of Iowa, grew by 713 net votes. The number of votes by which Trump boosted his total: 711. The number of votes Joe Biden garnered over the figure recorded by Hillary Clinton: 2.

That figure may be skewed a bit by the absence of leftward-leaning Grinnell College students because of COVID-related remote learning, but the figure still is arresting. Poweshiek is a rural county with population density of only 32 people per square mile; Polk County, home of Des Moines, has a population density 26 times as great.

“Rural America is the most distressed part of the country, and so when we talk about things that governments do, it seems to leave rural America behind,” said Caroline Tolbert, a University of Iowa political scientist. “Trump’s message was aimed at communities left behind. The country is a complex map of haves and have-nots. People here are struggling for representation and needing help. Trump’s themes spoke to them.”

The trend is replicated across the state. Lee County, along the Mississippi in far southeastern Iowa, added 1,296 voters in 2020 — and they went for Trump by almost exactly a 3-to-1 ratio. Only a dozen years earlier, Democratic nominee Barack Obama won nearly three-fifths of the votes in the county.

“These people — many of them lower-income whites — have grievances, and they’re not being addressed by the Acela corridor,” said Carleton College political scientist Steven Schier, who was reared in Fort Madison, the county seat, and educated at Simpson College in Indianola in south-central Iowa. “You couldn’t find a more difficult audience to sell critical race theory than Lee County. They’re not feeling too privileged because of their white race.”

Iowa is a state where Democrats won six of the seven elections from 1992 to 2012. But Trump’s 9 percentage point victory in 2016 represented a 15-point swing from Barack Obama’s victory four years earlier. And Trump took a greater percentage of the vote in Iowa in 2020 than he had four years earlier.

This is important because in the six elections from 1992 to 2012, the Iowa vote never deviated from the national result by more than 1 percentage point.

During the mid-1980s farm credit crisis, Joan Blundall, then the director of the rural response program at the Northwest Iowa Mental Health Center, told me that Iowans had “a hostile view of the entire economic system. They’ve been locked out of prosperity, they think the political system simply can’t be trusted, and they distrust both the Republicans and the Democrats.”

Now they distrust Democrats more, and today’s Republicans — with the exception, of course of Sen. Chuck Grassley, who is almost 89, has been on Capitol Hill for 47 years and is running for reelection — bear little resemblance to earlier Republicans.

Two of those new-age Republicans turned up in Iowa recently, stirring passions and, from some viewpoints, trouble.

No political figure plans an August respite in Iowa; the state does not plaster “Vacationland” on its license plates like Maine does, and it does not offer the sort of lakeside fun found in Wisconsin and Michigan, nor the mountain retreats that make Colorado and Utah summertime hiking destinations. But with its early presidential caucuses and its sophisticated voter base, Iowa is a political test kitchen. So when former Secretary of State Mike Pompeo and GOP Reps. Marjorie Taylor Greene of Georgia and Matt Gaetz of Florida landed in Iowa last year, they didn’t have kayak trips and sandcastles in mind.

The visitors argued that Trump was the rightful president, that moderate Republicans weren’t Republicans at all and that, as Greene put it, the country was threatened by a conspiracy of the news media, Democrats and big tech companies — a new “axis of evil.” No one noted that her remarks were an echo of the charge the aviator Charles Lindbergh made in Des Moines almost 80 years earlier, when he said in 1941, less than three months before Pearl Harbor, “The three most important groups who have been pressing this country toward [entry into World War II] are the British, the Jewish [sic] and the Roosevelt Administration.”

So of all the places where the future of American politics is being determined — the suburbs where moderate Democrats inched to hard-won 2018 midterm victories in Trump congressional districts, states where Republican legislatures have enacted laws restricting voting, places where the 2020 election results prompted bitter disputes — one of the important battlegrounds is Iowa, where Jonathan Dolliver, a Republican who served in the Senate from 1900 to 1910, said, “Iowa will go Democratic when Hell goes Methodist.”

David M. Shribman is the former executive editor of the Pittsburgh Post-Gazette.