President Trump is trying to cast his Iran war as all but over, a done-and-dusted success.

But after years of trying to impose his own reality on the world, he has now run into a crisis that is not bending to his narrative.

“It’s a new regime,” Mr. Trump said in a Fox Business interview that aired on Wednesday, referring to Iran’s new leaders. “We find them pretty reasonable to be honest with you, by comparison pretty reasonable.”

It was the latest instance of Mr. Trump’s trying to spin a “regime change” accomplishment in Iran, even though analysts believe the war may have only increased the internal sway of Iran’s Islamic Revolutionary Guards Corps, the hard-line military force that has long been a major player in Iran’s politics and economy. The new supreme leader, Ayatollah Mojtaba Khamenei, has not been seen in public since he replaced his father, who was killed at the start of the war, but his elevation as head of state has been another symbol of continuity.

“Most generously you could say there is a leadership change,” said Behnam Ben Taleblu, the senior director of the Iran program at the Foundation for Defense of Democracies, a Washington think tank with a hawkish stance on Iran. “It is incorrect for the proponents of the conflict to frame this as a change for the better.”

Indeed, trade through the Strait of Hormuz remains far from normal and Iran’s government is not bending to Mr. Trump’s demands on its nuclear program.

But in Mr. Trump’s telling, U.S. victory in Iran is already clear. In the Fox Business interview, reprising his frequent comments of the last two weeks, Mr. Trump asserted that Iran’s navy, air force and antiaircraft equipment had all been wiped out, along with many top officials. If Iran did not rule out nuclear weapons, Mr. Trump said, “we will be living with them for a little while, but I don’t know how much longer they can survive.”

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