The newly released Census data shows that people are moving with greater frequency from Clinton-voting counties to Trump-voting counties than the other way around, but the Republican party shouldn’t be so quick to celebrate.
The charts in this article were produced by the Indeed Hiring Lab where the author, Jed Kolko, works as chief economist.
The 2017 Census local population estimates, released this morning, show that Americans are moving from blue counties to red counties, and at a quickening pace. The flow of people from blue to red counties has picked up in recent years, steadily increasing since 2012, and the exodus is greatest in dark-blue counties—those where Hillary Clinton beat Donald Trump by more than 20 percent. (Blue and red refer to whether Clinton or Trump got more votes in 2016; dark and light refer to whether the margin was at least 20 percentage points. Data on voting was not available for Alaska counties, which were omitted.)
What's driving this? The continued suburbanization of America underlies this shift toward red counties. But the news isn't all grim for blue America. Blue counties got a population boost from international migration, partly offsetting losses from domestic migration. And, the fastest-growing red counties are moving to the left and could turn blue the next time around.
The Census breaks population growth into three components: net domestic migration, international migration, and natural increase (births and deaths). Let's start with domestic migration, which accounts for most of the differences the Census shows in population growth. In 2017 (technically, the year ending July 1, 2017), dark-blue counties lost 0.7 percent of their population due to net domestic migration—in other words, more people moved out of these counties to the rest of America than moved in. Light-blue counties were slightly negative, while red counties had more in-movers than out-movers. The flow of people from blue to red counties has picked up in recent years, steadily increasing since 2012.
Yet international migration and natural increase offset some of the domestic migration from blue to red counties. International migration contributed six times as much population growth in dark-blue counties as dark-red counties. Put another way, 80 percent of net international migration in 2017 was in blue counties, and 56 percent in dark-blue counties. Natural increase—that is, births minus deaths—also favors blue counties, mostly because red counties have an older population and therefore higher death rates. The contribution of births to population growth is similar in red and blue counties, on average, and there are both red and blue places where birth rates are high. Population growth due to births tends to be highest in places with large Latino or Mormon communities. Among large metros, population growth due to births is highest in dark-blue El Paso and McAllen-Edinburg-Mission, Texas, and dark-red Provo-Orem and Ogden-Clearfield, Utah.
Combining all sources of population changes—domestic migration, international migration, and natural increase—dark-blue counties grew more slowly than other counties, and had slower growth than in previous years.
The differences between red and blue counties echo the broader trend toward the continued suburbanization of America. Urban counties of large metros are now growing slowly; they also tend to be dark blue. The fastest-growth counties are the lower-density suburbs of large metros, which lean red. However, non-metropolitan areas, which vote strongly red, have seen their population stagnate or shrink. So, while red America includes booming outlying suburbs it also includes struggling rural areas.
Will the population shift toward red places hurt Democrats and help Republicans? Not necessarily. Red places might win bragging rights for drawing people in, and it's possible that blue-to-red migrants adopt some of the political views of their new neighbors. Yet, at the same time, it's also possible that migrants from blue to red counties bring their politics with them. A 2016 essay titled "Go Midwest, Young Hipster" even proposed migration as a political strategy to help Democrats win outside their traditional strongholds.
Unfortunately, the new Census population data don't tell us the demographics, politics, or anything else about the individuals who are moving from blue to red counties. Still, one clue might lie in how the politics of fast-growing places are changing. Among red counties there's a huge difference between places that are swinging right and those moving toward the center. In the counties that voted for Trump in 2016 but voted at least 10 percent more strongly for Romney in 2012—that is, those that moved toward the center in 2016 —population grew at 2.5 percent in 2017, more than three times the national growth rate of 0.7 percent. These include several suburban Sunbelt counties in metros like Atlanta and Dallas, as well as many Utah counties. However, counties that swung right, flipping from Obama in 2012 to Trump in 2016—including many counties in New York State, Pennsylvania, Ohio, and Michigan—grew on average just 0.2 percent in 2017.
Therefore, the population is shifting not simply from blue to red places, but toward red places that are themselves moving left. Current population trends might turn out to be good news for the Democrats after all.
Voting data from from Dave Leip's Atlas of U.S. Presidential Elections.