The flip side of this fondness for civilized law and order is revealed when Mr. Trump extols the “unbelievable job” of President Rodrigo Duterte of the Philippines, who has orchestrated the extrajudicial killing of thousands on the grounds of fighting a war on drugs. Certain nonwhite, non-Western strongmen, it seems, can be brought into the magic circle of civilization if they are stamping out savagery. In May, Mr. Trump took his first foreign trip to Saudi Arabia. In a red-carpeted Riyadh he found an ally against “barbaric criminals,” not to mention a lavish purchaser of American arms. In so doing, he joined a long line of presidents who backed third world autocrats as bastions of modernity and stability. This time the president dispenses with lip-service to democracy or human rights.

America First nationalism isn’t dead, though. It lingers in the background. The administration’s decision to withdraw from the Paris climate accord was pure America First, replete with paeans to Pittsburgh over the center of French civilization. The president may yet mount a serious effort to restrict trade, despite a lull after he scuttled the Trans-Pacific Partnership. Nonetheless, “civilization” seems likely to continue to occupy the fore of foreign policy under the Trump administration. It may be the only doctrine able to reconcile Mr. Trump’s material commitment to America’s global primacy with his ideological aversion to liberal universalism.

All this makes President Trump something other than either the narrow realist that his critics fear or the passing oddity for which his critics hope. Like it or not, the emerging Trump doctrine has deep roots in American tradition. Six months in, the time has come for advocates of American world leadership to own up to a fact: Donald Trump is one of you.

To be precise, Mr. Trump appears to be evolving into a kind of neoconservative. Before becoming associated with George W. Bush’s “freedom agenda,” many neoconservatives reviled Soviet Communism but were less than enamored with the goal of exporting democracy and human rights. Scorning the flabby norms of the liberal international order, they placed their trust in the muscular assertion of American power, deeming it the real guarantor of their country’s interests and the world’s civilized values alike.

Like earlier neocons, Mr. Trump looks at the world and sees unceasing threats that experts understate. In the 1970s, prominent neoconservatives formed a “Team B” to challenge the C.I.A.’s estimate of Soviet capabilities and reinvigorate the Cold War. Later, George W. Bush’s administration created an intelligence unit that hyped the Iraqi threat. Mr. Trump, too, mistrusts professionals in the State Department, whose funding he seeks to slash, and in the intelligence agencies, whose honesty and competence he has impugned. Like neoconservatives, he glorifies martial values and seeks to build up the military. Unsurprisingly, this foreign policy has received recent praise from neoconservatives like Elliott Abrams, an erstwhile critic and former Bush and Reagan foreign policy staffer. The commentator Charles Krauthammer, a frequent Trump critic, conferred the gold standard on the Warsaw speech: “Reaganesque.”

Even so, one should not expect Mr. Trump simply to replicate the policies of neocons past. Under the banner of civilization, he gains the flexibility to cast Russia not only as an Eastern enemy but alternately as a Western ally, standing tall against terrorist barbarism and secular decadence. Such an image, promoted by President Vladimir Putin himself, has turned Russia into the north star of right-wing authoritarians on both sides of the Atlantic.