Unswayed by Allies, Trump Is Expected to Leave Iran Deal, Diplomats Say

“It can’t be saved,” said Aaron David Miller, a longtime former diplomat now at the Wilson International Center for Scholars. “Whatever Trump decides, it’s the beginning of the end of the accord, either death by one, or 1,000, cuts.”

Over the past three weeks, senior officials from France, Britain and Germany flew to Washington to make a case that ditching the accord was a diplomatic mistake. On Sunday, Boris Johnson, the British foreign secretary, was the last to make those arguments, writing in The New York Times that “now that these handcuffs are in place, I see no possible advantage in casting them aside.”

By the middle of Monday, his visit seemed a last gasp: He was told that the decision was all but preordained, officials said.

President Emmanuel Macron of France and Chancellor Angela Merkel of Germany similarly argued that the Iran accord was flawed but could be built upon. The allies had suggested that the West could impose new sanctions against Iran’s ballistic missile development and armed support for the Syrian regime, for Hezbollah, for Hamas and Islamic Jihad in the Palestinian territories — but keep the nuclear deal intact.

“My view — I don’t know what your president will decide — is that he will get rid of this deal on his own, for domestic reasons,” Mr. Macron told a group of reporters in Washington during his visit last month.

But it has been difficult for Europeans to answer Mr. Trump’s demands because it is clear that Iran will not agree to reopening the terms of the accord itself. And if it were to be reopened, Iran had a series of demands of its own.

Should Mr. Trump withdraw from the accord, Iran could accurately claim that Washington was the first to violate it — a propaganda win. And Iran would be free, if it chose, to resume fuel production, according to diplomats who spoke on the condition of anonymity to discuss the sensitive negotiations.