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Why The Suburbs Have Shifted Blue

President Trump spent the last few months of the presidential campaign appealing to — and sometimes even pleading with — suburban voters. At a rally in Pennsylvania in October, Trump called out suburban women specifically, saying that “they should like me more than anybody here tonight because I ended the regulation that destroyed your neighborhood,” referring to his administration’s move to end a government program aimed at reducing segregation in suburban areas. “I ended the regulation that brought crime to the suburbs,” said Trump. “[A]nd you’re going to live the American dream.”

It was plain to see that Trump wasn’t talking to all suburbanites, though. He appeared to have a specific vision of the suburbs in mind: Something like the modern day equivalent of the white, well-to-do characters from 1950s sitcoms who had big, well-manicured lawns and white picket fences, agreed with their neighbors about most things — from which presidential candidate to support to what makes a good tuna casserole — and were, in the past, the targets of racial dog-whistles like Trump’s.

Only this strategy didn’t work. Because this version of suburbia is increasingly hard to find.

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Suburban and exurban counties turned away from Trump and toward Democrat Joe Biden in states across the country, including in key battleground states like Pennsylvania and Georgia. In part, this may be because the suburbs are simply far more diverse than they used to be. But suburbs have also become increasingly well-educated — and that may actually better explain why so many suburbs and exurbs are turning blue than just increased diversity on its own.

According to Ashley Jardina, a political science professor at Duke University who studies white identity politics, it’s not that racial diversity isn’t a factor. Among white people, at least, educational attainment is often a proxy for how open they are to growing racial diversity, with more highly educated white people likely to think increased racial diversity is a good thing. “Education is so important because it’s intertwined with racial attitudes among white people,” Jardina said.

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No matter how you slice it, it’s clear that communities that were pretty much uniformly white only a few decades ago are now far more racially diverse, with Black, Hispanic and Asian Americans making up larger shares of suburban and exurban populations than ever before. According to our analysis of data from a “diversity index” developed by USA Today that calculates the chance that any two people chosen at random from a given area are of different races or ethnicities, most suburbs have grown at least somewhat more diverse over the past 10 years. That’s particularly true in some of the states — like Georgia, Wisconsin, Pennsylvania and Michigan — that were pivotal for Biden this year.1

On the surface, those demographic shifts may seem like good news for Democrats, since nonwhite voters are much more likely to identify as Democratic than white voters. But when we dug into how these diversifying parts of the country have actually voted, we didn’t find a uniform shift toward from FiveThirtyEight’s urbanization index, which uses the average number of people living within a five-mile radius of every census tract to calculate the density of a given area, we limited this analysis to the 670 counties where at least a plurality of the county was classified as either suburban or exurban. We excluded those counties where the most common density level was either urban or rural.

">2 Some suburbs that grew more racially diverse over the past decade saw a smaller swing toward Biden than others — or even moved slightly further into Trump’s column. And other suburbs that didn’t diversify much at all still became much bluer in 2020.

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Rather, it was education — and particularly how much more educated a place has gotten over the past 10 years3 — that was more closely related to increased support for Biden (especially once accounting for how educated a county was in 2010). Growing racial diversity in an area was still important, since the suburban counties that saw the biggest swing toward Trump were the ones that remained less racially diverse and less educated. But the political swing among diversifying counties was much less uniform than it was in counties that became more educated.

Take Henry County, Georgia, a mostly exurban part of the Atlanta metropolitan area. Voters there narrowly backed Hillary Clinton by 4 points in 2016, but they supported Biden by a whopping 20 points this past November — a 16-point Democratic swing. What happened? Henry County was already pretty diverse, but it became even more so in the past decade. Once majority non-Hispanic white, the share of its Black population is now nearly equal to its white share. Meanwhile, the share of the population with a college degree grew slightly faster than was typical across other suburban and exurban counties. This made Henry one of the many increasingly diverse and educated counties in the Atlanta area that shifted to the left from 2016 to 2020, helping Biden become the first Democratic presidential candidate to carry the state since 1992.

And it’s suburbs like Henry that produced some of the swiftest and most dramatic political shifts of the 2020 election, according to William Frey, a demographer and senior fellow at the Brookings Institution’s Metropolitan Policy Program. The patterns we observed in Henry County can be seen in suburbs across the Sun Belt. Shifting suburban populations in states like Texas and Arizona have made presidential elections there much more competitive in a relatively short period of time, while according to Frey, demographic change has been happening in suburban areas in Rust Belt states like Michigan and Wisconsin too, but at a slower pace.

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What about places that become either more diverse or more educated, but not both? Suburban and exurban counties that grew more diverse but did not become more educated still swung toward Biden in 2020, but by a much smaller margin. It’s especially striking when you compare these places to areas that became much more educated but not more diverse, as those places actually had moved more toward Biden, on average.

Consider Volusia County, Florida, a suburban-exurban county northeast of Orlando in central Florida. Volusia became marginally more Republican this year, as Trump won it by 14 points after winning it by 13 points in 2016. This, despite the fact that Volusia has become more diverse over the past decade, primarily through an increase in its Hispanic population (although the county is still roughly 70 percent non-Hispanic white). However, the share of Volusia’s population with a four-year college degree hasn’t increased as much as in other suburban and exurban places.

It’s also possible that because the population was less educated as a whole, the white residents were more likely to respond to the county’s growing diversity by becoming more conservative — canceling out some of the effects of having a growing nonwhite, Democratic-leaning share of the community. In her own research, Jardina has found similar dynamics at play, although she hasn’t focused on the suburbs specifically. In general, though, Jardina said, “[W]hites who have a higher level of racial identity and live in places where there’s been a much greater change in the foreign-born population are much more likely to vote conservatively.”

That may help explain why suburban and exurban areas like Volusia County that became notably more diverse but not more educated didn’t move as much to the left as places that became more educated but not more diverse. Take Ottawa County, Michigan, which sits along the coast of Lake Michigan as part of the Grand Rapids metropolitan area. The county remains pretty Republican, but Trump only carried it by 21 points this year after winning it by 30 points four years ago — a 9-point swing toward the Democrats. And although the racial and ethnic makeup of Ottawa’s population hasn’t changed much since 2010, the share that holds a bachelor’s degree has shot up from 29 percent to 34 percent, which might explain the county’s swing. Overall, the Democratic gains there were part of a larger swing in the traditionally Republican Grand Rapids region that helped Biden carry Michigan.

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So what do these trends mean for Democrats — and Republicans — going forward? Jardina stressed to us that in the short term, demography is not destiny. Democrats might struggle to reproduce Biden’s strong performance in the suburbs, particularly if their Republican opponents don’t rely as heavily on racialized appeals and transparently racist tropes as Trump. “The big question mark for me is what happens in these suburban areas in two years or four years if [Republican candidates] adopt a similar strategy to Trump but with more competence and decorum,” Jardina said. “I’ll put it this way — I don’t think Republicans have lost their opportunity to stay competitive in the suburbs.”

On the other hand, both Frey and Jardina said it’s possible that the demographic realignment of the suburbs could end up creating a more lasting political shift — one in which the suburbs and exurbs look and vote a lot more like urban areas, and a lot less like more rural places. Frey predicted, though, that the big political shifts we saw this year in places like the Sun Belt might persist — or even accelerate — simply because they map better onto the speed and breadth of the demographic changes in those areas. But a lot will depend on Democrats’ ability to mobilize the diverse groups that now are looking more and more like typical suburban voters.

“The future of the Democratic Party is clearly with these younger, more diverse, more educated populations,” Frey said. “But they have to figure out how to keep them energized and voting.”

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  1. We used the 2014-18 and 2006-10 American Community Survey to calculate the diversity of a county and how it changed over time, with very homogeneous counties scoring close to zero while very diverse places scored closer to one. Note that there are some important political changes that may not be captured by looking at growing diversity alone — for example, while most homogeneous places in the U.S. are very white, there are a few heavily nonwhite places that have low diversity marks, such as overwhelmingly Hispanic counties along the U.S.-Mexico border, some of which swung dramatically toward Trump this year. Nevertheless, the USA Today diversity index is a good indicator for how most suburban and exurban counties across the country became more diverse in recent years.

  2. Using data from FiveThirtyEight’s urbanization index, which uses the average number of people living within a five-mile radius of every census tract to calculate the density of a given area, we limited this analysis to the 670 counties where at least a plurality of the county was classified as either suburban or exurban. We excluded those counties where the most common density level was either urban or rural.

  3. For the purposes of this analysis, education is measured by the share of a county’s population age 25 or older with at least a bachelor’s degree.

Geoffrey Skelley is a senior elections analyst at FiveThirtyEight.

Elena Mejía was a visual journalist at FiveThirtyEight.

Amelia Thomson-DeVeaux is a senior editor and senior reporter for FiveThirtyEight.

Laura Bronner is a senior applied scientist at ETH Zürich and FiveThirtyEight’s former quantitative editor.