I took a list of all 981 U.S. counties 1 with 50,000 or more people 2 and sorted it by the share of the population 3 that had completed at least a four-year college degree. Hillary Clinton improved on President Obama’s 2012 performance in 48 of the country’s 50 most-well-educated counties. And on average, she improved on Obama’s margin of victory in these countries by almost 9 percentage points, even though Obama had done pretty well in them to begin with.
.Although they all have highly educated populations, these counties are otherwise reasonably diverse. The list includes major cities, like San Francisco, and counties that host college towns, like Washtenaw, Michigan, where the University of Michigan is located. It also includes some upper-middle-class, professional counties such as Johnson County, Kansas, which is in the western suburbs of Kansas City. It includes counties in states where Clinton did poorly: She improved over Obama in Delaware County, Ohio, for example — a traditionally Republican stronghold outside Columbus — despite her numbers crashing in Ohio overall. It includes extremely white counties like Chittenden County, Vermont (90 percent non-Hispanic white), and more diverse ones like Fulton County, Georgia, where African-Americans form the plurality of the population. If a county had high education levels, Clinton was almost certain to improve there regardless of the area’s other characteristics.
Then Nate took the 50 least educated large counties.
These results are every bit as striking: Clinton lost ground relative to Obama in 47 of the 50 counties — she did an average of 11 percentage points worse, in fact. These are really the places that won Donald Trump the presidency, especially given that a fair number of them are in swing states such as Ohio and North Carolina. He improved on Mitt Romney’s margin by more than 30 points (!) in Ashtabula County, Ohio, for example, an industrial countyalong Lake Erie that hadn’t voted Republican since 1984.
And this is also a reasonably diverse list of counties. While some of them are poor, a few others — such as Bullitt County, Kentucky, and Terrebonne Parish, Louisiana — have average incomes. There’s also some racial diversity on the list: Starr County, Texas, is 96 percent Hispanic, for example, and Clinton underperformed Obama there (although she still won it by a large margin). Edgecombe County, North Carolina, is 57 percent black and saw a shift toward Trump.
How do we know that education levels drove changes in support — as opposed to income levels, for example? It’s tricky because there’s a fairly strong correlation between income and education.4 Nonetheless, with the whole country to pick from, we can find some places where education levels are high but incomes are average or below average. If education is the key driver of changes in the electorate, we’d expect Clinton to hold steady or gain in these counties. If income matters more, we might see her numbers decline.
As it happens, I grew up in one of these places: Ingham County, Michigan, which is home to Michigan State University and the state capital of Lansing, along with a lot of auto manufacturing jobs (though fewer than there used to be). The university and government jobs attract an educated workforce, but there aren’t a lot of rich people in Ingham County. How did Clinton do there? Just fine. She won it by 28 percentage points, the same as Obama did four years ago, despite her overall decline in Michigan.
And in most places that fit this description, Clinton improved on Obama’s performance. I identified 22 counties5 where at least 35 percent of the population has bachelor’s degrees but the median household income is less than $50,0006 and at least 50 percent of the population is non-Hispanic white (we’ll look at what happened with majority-minority counties in a moment, so hang tight). Clinton improved on Obama’s performance in 18 of the 22 counties, by an average of about 4 percentage points.
So yeah, it's pretty clear at this point that Donald Trump's play to a combination of fear, ignorance, and white identity politics (and a need for "beneficent" white identity politics to help less educated, poorer non-white areas) was the key to his victory.
And he did it masterfully.