“The People vs. Democracy,” by Harvard’s Kennedy School faculty member Yascha Mounk, says that for much of the 20th Century, capped by the collapse of communism, the political system of liberal democracy flourished. That system marries formal democracy of popular elections with liberal institutions that guarantee the rule of law and individual liberties. The popularity of this system (in, say, Poland and Hungary after the collapse of the Soviet Union, in western Europe and in the U.S.) was the result of three constraints against an underlying high risk of political chaos: Rising incomes, cultural hegemony in countries, and mass communication that was controlled by the political and financial elite. These three constraints are now largely gone, due to economic underperformance for most people, immigration and the internet. As a result, it is much easier now for people to express their desire for authoritarian figures who say they can fix everything, non-objection to military rule, removal of liberal institutions such as an independent court system and independent media, and hostility to immigrants.
My comment: the traditional destinations of immigrants, mainly the Northeast, some large mid-west cities, and the West Coast, have a high tolerance for cultural diversity. The rise in immigration since the 1960s was managed fairly well. The main opposition to immigration today is from inland, more rural communities which until the 1990s did not experience much immigration in the 20th C.