Why more than 30 counties switched parties after 40 years of loyalty

The pattern here is that the counties had been pretty consistent in their support of the Democratic candidate, like Trumbull. But in 2016, there was a sharp shift toward Trump. The outlier in this case is Elliott County, Kentucky, which had a truly staggering shift from 2012, voting nearly 47 points more Republican on net. The county is a distillation of the Democrats’ problems with blue-collar voters, going from very, very blue to very red in relatively short order.

So why did these reliably blue counties suddenly decide to flip to Trump? There’s a clear correlation between the degree to which the county’s vote choice changed over the last four years and the density in the county of Trump’s strongest demographic.