Trump's 2016 primary campaign (not the general) had an ethnic angle that went largely untalked about. It revealed a cultural split in the American Midwest between the descendants of Germanic immigrants who hated his boastfulness and the descendants of Old Americans who loved it.

After the Iowa cacucus I fiddled around with a NCSS spreadsheet of Iowa counties and discovered that the % of county who identified as Dutch in the census was the best negative predictor of Trump’s vote count, more important even than the % of bachelor’s degrees.

There aren’t many Dutch people in America. Their highest concentration by far (57.7%) is in ultra-religious Sioux County Iowa which also gave Trump his lowest shared of the vote (10.9%, his average was 24.3%). Others have noticed the same thing: https://www.aei.org/op-eds/the-most-interesting-county-in-iowa-trumps-worst-county-and-his-best-county-in-one-place/