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The 2016 presidential election showed a nation that is divided not just along partisan lines but geographic ones, too. Accentuating recent trends, Democrat Hillary Clinton dominated urban areas, while Republican Donald Trump owed his victory to strong support in rural parts of the country.

Clinton carried 88 of the 100 largest counties, accounting for her popular vote win. But among smaller counties, Clinton won just over 420 while Trump prevailed in more than 2,500.

The urban-rural divide is getting a lot of attention in the wake of last week's results, but it's been part of U.S. politics for decades. Back in 2008, journalist Bill Bishop identified the degree to which Americans were dividing themselves into separate enclaves in an influential book called The Big Sort: Why the Clustering of Like-Minded America is Tearing Us Apart.

With this sort of cultural and political segregation growing deeper, Governing spoke with Bishop, a contributing editor at the Daily Yonder, which covers rural issues. We talked about how people choose where they live, the likelihood of a mass migration of Democrats to rural America and the importance of political enemies.

The following discussion has been edited for clarity and length.

What strikes you most about this election?

The rapid increase in the number of people who live in counties where this remarkably close election wasn't close at all. Four years ago, about half the people lived in one of these landslide counties, where one candidate or the other wins by 20 points or more. That's our way of measuring political segregation. This year, that increased to 60.4 percent.

In terms of geography, in 2012, 65 percent of counties were in that landslide category. This time, it was 80 percent.

In your book, you say that only about a quarter of the people lived in landslide counties back in 1976, another close presidential election. Now, it's a big majority. What sort of effect does that have?

The result is that you have increasing populations where people talk to those who agree with them politically. They hear stories and facts and figures that support their beliefs.

Over time, social psychology research will tell you that these like-minded groups become more extreme in the way that they're like-minded. Put a group of conservatives in a room and they'll become more conservative. It's just the same with liberals.

Are people consciously choosing not to live among people with different political beliefs?

Our sense was that this sort wasn't at root political, that people were sorting into communities where they could find people with the same lifestyle tastes. This time, those lifestyle choices translated into political choices.

The Pew Research Center showed that conservatives prefer houses that are farther apart and where you have more room, even if that means you have to drive more. Liberals like where you can walk to school and work.

Density becomes a marker for politics. Democrats have really packed themselves into the most dense counties in the country as well as big cities. Republicans dominate in all other geographic areas. That also means that gerrymandering is something people have done to themselves.

There's been a lot of media chatter about the idea that Democrats are going to have to spread themselves out more. Do you think Democrats will really pack up and move to the Rust Belt to shore up the party's strength?

No way. Our impression is that people are even less likely to visit. When we moved to central Texas, people from Austin would visit the barbecue places and revel in central Texas places. Now, people have said to us, "It's not fun; it's foreign; I'd be afraid."

There's also been a lot of talk about how liberals and the media need to do a better job of understanding the concerns of rural America. Do you think the reverse is true, that people who live in what they call the "real America" should understand the culture of the big cities on the coasts?

There are two things going on. The cities are sources of economic growth and diversity, but they also breed distrust and a lack of support for community institutions.

That's not the kind of community that people in a lot of parts of the country want to belong to. There's a paradox going on that is irresolvable.

We do seem to be splitting into two Americas, where people can't comprehend the politics on the other side. The rural areas don't feel like they're part of the global economy, which is one reason they were willing to support Trump. On the other hand, we've already seen lots of protests against Trump, particularly in cities he couldn't carry, such as New York, Oakland and Portland, Ore. A lot of people feel like strangers in their own land.

We are. So we're living with the consequences.

Honestly, I don't know how you get around what has become human nature. I've been reading Umberto Eco's essay, "Inventing the Enemy," where he writes that having an enemy is important not only to measure progress but measure our system of values. In other words, we need an enemy to know who we are and who we are not.

That also tells you that politics now is about identity and self expression and not about policy. That's what a lot of people miss. This really wasn't about policy decisions. This was about social identity, which is why the sorting took place to begin with.

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