It says something about the soundness of an idea that its currency owes less to its intrinsic merits than it does to the power of a man who has no ideas. It also says something about the intellectual plasticity of some newly minted national conservatives that they now champion a concept they would have disdained just three years ago.

But let’s give nationalism its due. Much of the world, including the free world, is organized around the concept of the nation-state. Nations — that is, people whose ties involve not merely citizenship but also ancestry, culture, history, language, territory and sometimes religion — can have deeper political cohesion, and inspire greater solidarity and mutual self-sacrifice, than mere states. Nationalism offers protection to “somewhere people” against the political and moral preferences of “anywhere people.” And transnational bodies like the European Union have largely failed the test of democratic representation and accountability.

The problem is, the United States is not “much of the world.” We are a sovereign state, not a nation-state. Unlike, say, Denmark, we have no official language and no state religion. Our identity is oriented toward the future, not the past. We do have birthright citizenship — though that, curiously, is something many of today’s national conservatives want to abolish. Our national borders have changed repeatedly and may change again.

America is the country under whose banner the descendants of slaves give military orders to the descendants of slave owners and stand guard alongside the children of immigrants from Greece and Mexico in places like Panmunjom. It’s where the biological son of a Syrian immigrant created our first trillion-dollar company. It’s where Jews celebrate Christmas by going out for Chinese food.

All this is the essence of America’s exceptionalism. It does not require open borders, rule by U.N. mandarins, obeisance to progressive pieties or any of the other ostensible predations of “globalism” that conservative nationalism claims to oppose.