There would have been no need to dispatch Vice President Mike Pence and Secretary of State Mike Pompeo to get a cease-fire had Mr. Trump himself not suddenly pulled American troops away from the border after a phone chat with Mr. Erdogan, the Turkish president and one of the strongmen rulers who melt the president’s heart. And Mr. Erdogan agreed to the cease-fire only after he effectively achieved everything he wanted, driving the Kurds far back from the Turkish border in a brief but murderous onslaught.

And only a day before Mr. Trump lifted sanctions on Turkey, Mr. Erdogan had spent several hours in Sochi, Russia, with a happy Mr. Putin — another of Mr. Trump’s paragons of effective governance — getting his marching orders from the Russian leader. With the Americans now out of the way and the Kurds in flight, Turkey and Russia will now jointly patrol the border area.

That Mr. Putin and Mr. al-Assad were now undisputed masters of Syria seemed not to faze Mr. Trump. Nor did he appear concerned that Turkey, a NATO ally whose country harbors American nuclear weapons, and whose leader recently let on that he is thinking of getting nukes of his own, was looking to buy state-of-the-art weaponry from NATO’s primary foe. “Other countries have stepped forward. They want to help, and we think that’s great,” Mr. Trump said, making clear that he meant not the European allies — who, as usual, got a passing whack from the back of the president’s hand — but rather Russian forces, recently accused in a Times investigative report of systematically bombing Syrian hospitals.

Perhaps it should not come as a surprise anymore that Mr. Trump sees anything he does as a great and unprecedented achievement, or that he views the Middle East as little more than a patch of “bloodstained sand” that Americans should stay out of, or that he puts more stock in dictators than in allies.

Yet it still comes as a shock that a man, already facing an impeachment inquiry over his misuse of the presidency to pressure Ukraine into doing his political dirty work, would not pause to wonder whether there might be a better way to conduct the foreign policy of the world’s most powerful — and once most respected — nation. In shaping his view on Ukraine, too, Mr. Trump apparently paid more heed to autocratic Ukraine-bashers like Mr. Putin and Prime Minister Viktor Orban of Hungary than to any of his own advisers.