In 2009, Christopher Caldwell wrote a brilliant, disquieting book about what this seething Muslim population portends for Europe. The marital behavior of Muslim immigrants gets special attention, in part because it demonstrates the depth of the cultural problem. Caldwell puts it bluntly: “In a lot of European countries, marriage is not just an aspect of the immigration problem; it is the immigration problem.”

That’s because many Muslim immigrants don’t marry Europeans or even European-born “westernized” Muslims; they import spouses, often underage girls, from their ethnic homelands. In Germany, half of ethnically Turkish Germans seek spouses in Turkey. In Denmark, a large majority of Turks and Pakistanis do the same—and not just immigrants, but also second and third-generation descendants of immigrants. In France, family-related immigration makes up 78 percent of permanent legal immigration. Perhaps this wouldn’t be a problem if all these spouses were assimilating, but they’re not.

Such trends refute the empty platitudes of European leaders such as former president of the Italian Senate Marcello Pera, who said that any migration from place A to place B showed the superiority of B. That Muslims are migrating to Europe en masse but rejecting Europeans as suitable spouses, “shows that you can migrate to a place while being hostile to it, or at least while holding it in no special regard,” writes Caldwell. “Yes, immigrants ‘just want a better life,’ as the cliché goes. But they don’t necessarily want a European life. They may want a Third World life at a European standard of living.”