The corollary is in bold:
“People do care more about people who are like them — who speak their language, eat their food, share their customs and values. And when elites try to ignore those sentiments — or banish them by declaring that they are simply racist — this doesn’t make the sentiments go away. It makes the non-elites suspect the elites of disloyalty. For though elites may find something vaguely horrifying about saying that you care more about people who are like you than you do about people who are culturally or geographically further away, the rest of the population is outraged by the never-stated corollary: that the elites running things feel no greater moral obligation to their fellow countrymen than they do to some random stranger in another country. And perhaps we can argue that this is the morally correct way to feel — but if it is truly the case, you can see why ordinary folks would be suspicious about allowing the elites to continue to exercise great power over their lives.” — Britain’s Elites Can’t Ignore the Masses, by Megan McArdle
McArdle is writing about Britain’s coming vote to stay in or exit the EU, but the attitudes she describes are relevant to US politics.
UPDATE 14 August 2016: How Global Elites Forsake Their Countrymen