With the Iowa caucuses six days away, politicians will be crisscrossing the state, blowing through small-town Pizza Ranches, filling high school gyms, and flipping pancakes at church breakfasts.
What Iowans will not be seeing are Democrats. President Biden spoke Friday in Pennsylvania, and he and Vice President Kamala Harris both were in South Carolina over the weekend and on Monday. But Iowa, a state that once sizzled with bipartisan politics, launched Barack Obama to the presidency in 2008 and seesawed between Republican and Democratic governors, has largely been ceded to the G.O.P. as part of a remarkable sorting of voters in the Upper Midwest.
There is no single reason that over the past 15 years the Upper Midwest saw Iowa turn into a beacon of Donald J. Trump’s populism, North and South Dakota shed storied histories of prairie populism for a conservatism that reflected the national G.O.P., and Illinois and Minnesota move dramatically leftward. (Sandwiched in between, Wisconsin found an uncomfortable parity between its conservative rural counties and its more industrial and academic centers in Milwaukee and Madison.)
No state in the nation swung as heavily Republican between 2012 and 2020 as Iowa, which went from a six-percentage-point victory for Barack Obama to an eight-point win for Mr. Trump in the last presidential election.
Deindustrialization of rural reaches and the Mississippi River regions had its impact, as did the hollowing out of institutions, from civic organizations to small-town newspapers, that had given the Upper Midwest a character separate from national politics.
Susan Laehn, an Iowa State University political scientist who lives in the small town of Jefferson, Iowa, recounted how an issue that once would have been handled through discussions at church or the Rotary Club instead became infected with national politics, with her husband, the libertarian Greene County attorney, stuck in the middle: New multicolored lighting installed last summer to illuminate the town’s carillon bell tower prompted an angry debate over L.G.B.T.Q. rights, leaving much of the town soured on identity politics that they largely blamed on the national left.
Another issue: Brain drain. The movement of young college graduates out of Iowa and the Dakotas to the metropolises of Chicago and Minneapolis-St. Paul made a mark on the politics of all five states.
Michael Dabe, a 19-year-old business and marketing major at the University of Dubuque, near the western bank of the Mississippi River, has found a comfortable home in Iowa, where life is slower and simpler than in his native Illinois and politics, he said, are more aligned with his conservative inclinations.
But he expressed little doubt what he will be doing with his business degree once he graduates, and most of his classmates are likely to follow suit, he said.
“There are just so many more opportunities in Chicago,” he said. “Politics are important to me, but job security, being able to raise a family more securely, is more important, for sure.”
An analysis in 2022 by economists at the University of North Carolina, the W.E. Upjohn Institute for Employment Research, the University of Michigan and the University of Chicago of data gleaned from LinkedIn showed how states with dynamic economic centers are luring college graduates from more rural states. Iowa loses 34.2 percent of its college graduates, worse than 40 of the 50 states, just below North Dakota, which loses 31.6 percent. Illinois, by contrast, gains 20 percent more college graduates than it produces. Minnesota has about 8 percent more than it produces.
Even when young families look to move back to the rural areas they grew up in, they are often thwarted by an acute housing shortage, said Benjamin Winchester, a rural sociologist at the University of Minnesota in St. Cloud, Minn.; 75 percent of rural homeowners are baby boomers or older, and those older residents see boarded-up businesses and believe their communities’ best days are behind them, he said.
As such older voters grow frustrated and more conservative, the trend is accelerating. Iowa, which had a congressional delegation split between two House Republicans, two House Democrats and two Republican senators in 2020, now has a government almost wholly under Republican control, which has enacted boldly conservative policies that ban almost all abortions and transition care for minors, publicly fund vouchers for private schools and pull books describing sexual acts from school libraries. (The library and abortion laws are now on hold in the courts.) The congressional delegation is now entirely Republican after a 2022 G.O.P. sweep in House races and the re-election of Senator Charles E. Grassley.
Meantime on the east bank of the Mississippi, in Illinois, high-capacity semiautomatic rifles have been banned, the right to an abortion has been enshrined in law and recreational marijuana is legal. Upriver in Minnesota, pot is legal, unauthorized immigrants are getting driver’s licenses, and voting access for felons and teens is expanding.
Such policy dichotomies are influencing the decisions of younger Iowans, said David Loebsack, a former Democratic House member from eastern Iowa.
“These people are going, and I fear they’re going to keep going, given the policies that have been adopted,” he said.
The politics of rural voters in the Upper Midwest may simply be catching up to other rural regions that turned conservative earlier, said Sam Rosenfeld, a political scientist at Colgate University and author of “The Polarizers,” a book on the architects of national polarization. Southern rural white voters turned sharply to the right in the 1960s and 1970s as Black southerners gained power with the civil rights movement and attendant legislation, he noted.
But rural voters in the Upper Midwest, where few Black people lived, held on to a more diverse politics for decades longer. North Dakota, with its state bank, state grain mill and state grain elevator, has retained vestiges of a socialist past, when progressive politicians railed against rapacious businessmen from the Twin Cities. Even still, its politics have changed dramatically.
“Until relatively recently, there was a Midwestern rural white voter who was distinct from a southern rural white voter,” Mr. Rosenfeld said. “There was a real progressive tradition in the Midwest uncoopted by Jim Crow and racial issues.”
The rural reaches of Iowa now look politically similar to rural stretches in any state, from New York to Alabama to Oregon. And rural voters simply appreciated what Mr. Trump did for them, said Neil Shaffer, who chairs the Republican Party of Howard County, Iowa. Located along the Minnesota border, it was the only county in the nation to give both Mr. Obama and Mr. Trump 20-percentage-point victories.
Iowans like outsiders, and Mr. Obama’s charisma was winning, Mr. Shaffer said. But the self-employed farmers and small-business owners of Howard County were burdened by the Affordable Care Act, the Obama administration’s regulation of fresh water runoff, and depressed commodity prices.
There was skepticism of Mr. Trump and his abrasive, big-city behavior, Mr. Shaffer said, “but there’s that individual spirit in the Midwest that likes the Don Quixote railing against the big bad government, And people knew what they were getting.”
Kyle D. Kondik of the University of Virginia Center for Politics explains polarization as a tale of the top half versus the bottom half of the population scale. If more than half a state’s vote comes from dominant metropolitan areas, as is the case in Illinois and Minnesota, states tend to be Democratic. If smaller, rural counties dominate, states tend to move right.
Of the nine largest counties in Iowa, only one, Dubuque, switched from Mr. Obama to Mr. Trump in 2016. President Biden’s margin in those counties in 2020 was only three percentage points lower than Mr. Obama’s winning 2012 margin.
But Mr. Obama also carried 31 of the 90 smaller counties; Mr. Biden won none. As a group, Mr. Obama lost those rural counties by 2.5 percentage points to his Republican rival, Mitt Romney. Mr. Biden lost them to Mr. Trump by nearly 30 percentage points.
Mr. Kondik attributed some of that to Mr. Trump, whose anti-immigrant, protectionist policies diverged from traditional Republican positions. “He was a good fit for the Midwest,” he said.
Laura Hubka, who co-chairs the Howard County Democrats, remembered high school students driving trucks around town in 2016 with large Trump flags. It felt intimidating, she said.
“It was scary for a lot of people and scared a lot of Democrats inside,” Ms. Hubka said. “Trump spoke to a certain kind of people. People who felt like they were left behind.”
Chased by the shifting politics, she said, at least one of her children now plans to move his family across the border to Minnesota.
But the sweeping Republican victories in Iowa in 2022, when Mr. Trump was not on the ballot and the G.O.P. faltered in much of the country, point to other factors. Christopher Larimer, a political scientist at the University of Northern Iowa, again pointed to demographics. The huge groundswell of first-time 18-year-old voters who propelled Mr. Obama in 2008 were 22 and graduating college in 2012. By 2016, many of them had likely left the state, Mr. Larimer said.
“I don’t know if Iowa is any different from anywhere else; it’s caught up in the nationalization of politics,” he said. “Young people are moving into the urban core, and that’s turning the outskirts more red.”
If that urban core is in state, statewide results won’t change. If it is elsewhere, they will.
Mr. Winchester, the rural sociologist, said the perception of rural decline is not reality; regional centers, like Bemidji, Minn., or Pella and Davenport, Iowa, are thriving, and even if small-town businesses have closed, housing in those towns is filled.
But, he said, “many towns don’t know their place in the larger world. That concept of anomie, a sense of disconnection, is out there.”
Gary Hillmer, a retired U.S. Agriculture Department soil conservationist in Hardin County., Iowa, has drifted away from his Republican roots and said he struggled to understand the views of his Trump-supporting neighbors in the farm country around Iowa Falls.
“It’s hard to have a conversation with them to figure out why,” he said. “It’s frustrating, in that regard, because we ought to be able to talk to each other.”
Charles Homans and Cindy Hadish contributed reporting.