There was a critical word tucked into Donald Trump’s U.N. speech that went largely unnoticed but could have profound geopolitical implications, to the degree it reflects his and his teams’ thinking. That word is “sovereignty,” and we should all understand what the president means when he invokes it.

In his speech, Trump announced that America “will not be held hostage to an old, discredited ideology and experts that have been proven wrong over the years.” The ideology he is referring to is “globalism,” which he emphatically rejects. And in its place, he embraces the “ideology of patriotism.” It seems that international relations are a zero-sum game. If one believes globalism was responsible for lifting many nations out of poverty and that it was a positive gain for the world, one is not a patriot.

Trump’s speech was written by the most ideological member of his White House staff, Stephen Miller, whose perspective is essentially that of the ousted Steve Bannon. The former chief White House strategist is currently in Europe trying to build what he calls “the Movement,” an alliance of the new “illiberal” and populist-nationalist nations like Poland and Hungary, which are moving to adopt sovereignty as their governing principle in reaction to what he sees is the elitist dictatorship of the EU.

The case for sovereignty has been made most succinctly in a book that Miller is surely familiar with, John Fonte’s Sovereignty or Submission? Will American Rule Themselves or be Ruled by Others? This position also advocated by John O’Sullivan, who is a former editor of National Review who wrote the introduction to Fonte’s book as well as columns in praise of “national conservatism.” As Trump said in his speech, “We will never surrender America’s sovereignty to an unelected, unaccountable body”; America will remain “governed by Americans.” For that reason, he and John Bolton favor pulling the United States out of the International Criminal Court, which Trump says, “claims near universal jurisdiction over the citizens of every country.”

Trump emphasized trade as an area where America must assert its sovereignty, which brings us to China. He believes that waging a...