Logan Veret, 23, and Huey Dugas, 79, discuss farming on Dugas’s fourth-generation family farm in St. Martinville, La., last summer. Dugas’s farm produces 75,000 tons of sugar cane a year. (Photo by Annie Flanagan for The Washington Post)
Opinion writer

Our polarized political climate has many causes, but arguably the most important is our self-sorting into two demographic universes. The Pew Research Center finds:

Urban areas are at the leading edge of racial and ethnic change, with nonwhites now a clear majority of the population in urban counties while solid majorities in suburban and rural areas are white. Urban and suburban counties are gaining population due to an influx of immigrants in both types of counties, as well as domestic migration into suburban areas. In contrast, rural counties have made only minimal gains since 2000 as the number of people leaving for urban or suburban areas has outpaced the number moving in. And while the population is graying in all three types of communities, this is happening more rapidly in the suburbs than in urban and rural counties.

That sure sounds like the two political parties — one rural, graying, white and in decline, while the other is urban, diverse and growing. Sure enough we see:

Adults in urban counties, long aligned with the Democratic Party, have moved even more to the left in recent years, and today twice as many urban voters identify as Democrats or lean Democratic as affiliate with the Republican Party. For their part, rural adults have moved more firmly into the Republican camp. More than half (54%) of rural voters now identify with or lean to the GOP, while 38% are Democrats or lean Democratic.

We are used to hearing about the aggrieved white, aging and declining rural populations, but it is a two-way street, with urban voters feeling just as slighted. We have become, it seems, a country wallowing in self-pity.

The economic trajectory of the two halves of the country diverges more with each passing year. “The average earnings per worker in urban areas,” the report says, “were $49,515 in 2016, followed by $46,081 in the suburbs and $35,171 in rural areas, though these figures don’t account for differences in living costs across county types. And while the number of employed adults ages 25 to 54 rose in urban and suburban counties since 2000, it declined in rural counties overall.” That suggests we need to look at public policies that either encourage movement to more productive areas or figure out triage for rural regions.

The bad news for Republicans is that population growth in suburban areas (where Democratic political fortunes are improving) and urban areas outstrips the growth in rural areas. The share of college graduates (a group that normally leans Democratic) and of millennials is growing as well. The loss of white, college-educated women in particular may have a substantial negative effect on the GOP.

Unsurprisingly, race creates a huge divide that transcends even the rural/suburban/urban divide. (“In urban, suburban and rural areas, nonwhites are significantly more likely than whites to say that poverty, crime, racism, jobs, access to good doctors and hospitals, and access to high-speed internet are major problems in their local communities.”)

The figures on immigration are particularly noteworthy. Immigrant populations are largely concentrated in urban and suburban areas, but given the declining white population in rural areas, the change in demographics is noticeable. (“There is a large overlap between rural counties that have fewer U.S.-born residents than in 2000 and those that have fewer total residents than in 2000. In the vast majority of rural counties that lost population — 1,011 out of 1,025 — the number of U.S.-born residents declined, and there were not enough new immigrants to offset the loss.”)

Are we stuck with two separate, rather antagonistic subsets of Americans? Well, President Trump has certainly made the gap wider by playing the race card and governing in ways designed to please his base and infuriate everyone else. He has convinced many in his base that immigrants — rather than deficits in education, concentration of high-knowledge jobs on the coasts, the rise of the service economy — are responsible for their plight.

One way to heal the divide would be to end the style of governance that requires divisiveness. Trump is not going to change, but other politicians have the choice to end this style of politics. Moreover, policies that promote social and geographic mobility may help smooth out the economic and social gaps between rural America and more prosperous urban and suburban areas. A fully funded effort to stem the opioid abuse epidemic, especially fierce in rural areas, would also be a plus. And finally, both from a financial perspective and from self-interest, Democrats might want to consider a plan to vastly increase college attendance for rural residents. If there is one sure way to raise your income and move your politics left, it is to get a college education.