There are many explanations for the populist wave that’s been sweeping the Western world, but at least one common theme stands out: From America and Britain, to Germany and the Netherlands, to France and Sweden, voters have rebelled against political elites that seem increasingly cocooned from, and often dismissive of, the concerns expressed by ordinary people. No issue highlights this divide more clearly than the issue of immigration.

In 2016 alone, immigration played a crucial role in helping Donald Trump secure the Republican presidential nomination, in helping the pro-Brexit campaign win support from a majority of British voters, and in helping the populist “Alternative for Germany” party make historic gains in German regional elections.

Writing in Foreign Affairs, Fareed Zakaria tries to explain why immigration has become such a potent issue:

Unsurprisingly, the initial and most important issue Trump exploited was immigration. On many other social issues, such as gay rights, even right-wing populists are divided and recognize that the tide is against them. Few conservative politicians today argue for the recriminalization of homosexuality, for instance. But immigration is an explosive issue on which populists are united among themselves and opposed to their elite antagonists.

There is a reality behind the rhetoric, for we are indeed living in an age of mass migration. The world has been transformed by the globalization of goods, services, and information, all of which have produced their share of pain and rejection. But we are now witnessing the globalization of people, and public reaction to that is stronger, more visceral, and more emotional. Western populations have come to understand and accept the influx of foreign goods, ideas, art, and cuisine, but they are far less willing to understand and accept the influx of foreigners themselves — and today there are many of those to notice.

For the vast majority of human history, people lived, traveled, worked, and died within a few miles of their birthplace. In recent decades, however, Western societies have seen large influxes of people from different lands and alien cultures. In 2015, there were around 250 million international migrants and 65 million forcibly displaced people worldwide. Europe has received the largest share, 76 million immigrants, and it is the continent with the greatest anxiety. That anxiety is proving a better guide to voters’ choices than issues such as inequality or slow growth. As a counterexample, consider Japan. The country has had 25 years of sluggish growth and is aging even faster than others, but it doesn’t have many immigrants — and in part as a result, it has not caught the populist fever.

Zakaria’s point about Japan is a good one, and his entire article is worth reading. (Alas, it is behind a paywall.)