The president also has an overarching moral theory about American power, expressed in his 2009 contention in Prague that “moral leadership is more powerful than any weapon.”

At the time, Mr. Obama was speaking about the end of the Cold War—which, he claimed, came about as a result of “peaceful protest”—and of his desire to see a world without nuclear weapons. It didn’t seem to occur to him that the possession of such weapons by the U.S. also had a hand in winning the Cold War. Nor did he seem to contemplate the idea that moral leadership can never safely be a substitute for weapons unless those leaders are willing to throw themselves at the mercy of their enemies’ capacity for shame.

In late-era South Africa and the Soviet Union, where men like F.W. de Klerk and Mikhail Gorbachev had a sense of shame, the Obama theory had a chance to work. In Iran in 2009, or in Syria today, it doesn’t.

Then again, that distinction doesn’t much matter to this president, since he seems to think that seizing the moral high ground is victory enough. Under Mr. Obama, the U.S. is on “the right side of history” when it comes to the territorial sovereignty of Ukraine, or the killing fields in Syria, or the importance of keeping Afghan girls in school.