In 1985, the pollster Stanley Greenberg went to Macomb County, Mich., to figure out how a traditionally Democratic suburban area could have delivered a landslide for Ronald Reagan. Last year, he was back with a similar question: How could voters in a county that turned out twice for Barack Obama have defected in such large numbers that they arguably delivered Michigan to Donald Trump?
The research zeroed in on white Trump voters without a bachelor’s degree who were either Democrats or independents and had voted for Mr. Obama at least once. Focus groups detected the same underlying theme that had motivated the Reagan Democrats more than 30 years before: a view of America as divided between “us” — white, struggling and aggrieved — and a nonwhite “them.”
In 1985, “them” meant blacks across Eight Mile Road in Detroit. Last year, they were mostly immigrants, according to a study of the results by Democracy Corps, a nonprofit that Mr. Greenberg co-founded. Among whites, they both inspired a sense of betrayal and more than a little dread.
In a place that is more than 80 percent white, Mr. Trump’s Democrats share “pretty powerful feelings about race, foreignness and Islam that lead them to see white people as victims in a country feeling increasingly foreign to many of them,” the study noted.
This persistent sense of threatened white identity raises a prickly question about the country’s direction. Mr. Trump’s rise to the presidency prompted widespread efforts to understand the motivations of the white working-class voters who propelled him into the White House. It fueled scorching debates over the role that racism played in the presidential election.
Economists proposed that workers in distress because of trade and technological shocks would embrace more nativist politicians. In one study, David Autor of the Massachusetts Institute of Technology, along with several other researchers, concluded that counties whose workers were more exposed to Chinese imports have shifted notably toward the right in presidential and congressional elections since the turn of the century.
And yet some political scientists do not entirely buy the arguments. Diana C. Mutz of the University of Pennsylvania rejects the “economic hardship” idea to explain the 2016 election, proposing instead something called “status shock.” White voters fell for Mr. Trump, she argued, because they felt threatened by increasing numbers of minorities and the sense that the United States was losing its global dominance.
Whether Mr. Trump’s proposed barriers against imports and immigrants found support because of a sense of racial threat or out of distress over the loss of manufacturing jobs to China and other countries, ethnic unease is clearly shaping American politics and policy.
The share of America defined as white and non-Hispanic is shrinking. The United States is expected to reach “minority-majority” status in the early 2040s. A Cornell University sociologist, Daniel T. Lichter, suggests that if the demographic profile of poverty remains constant, by 2050 over 70 percent of America’s poor will be from today’s minority groups.
As the American demographic…