Just days ago, President Trump had appeared to embrace hopes for a diplomatic end to the war between Israel and Iran, holding off on immediate U.S. strikes and saying he might wait as much as two weeks to give negotiations a chance to work.

Less than 48 hours later, American bombers dropped their largest and most destructive conventional payloads on two of Iran’s nuclear facilities and fired missiles at a third, casting fresh doubt on the possibility that diplomats might get both sides to lay down their arms.

Mr. Trump had suggested for months that he wanted to avoid military action against Iran — but was prepared to take it if necessary. In mid-April, the president authorized 60 days of direct negotiations, which all but collapsed when Israel attacked Iran on June 13. Even then, Mr. Trump stopped short of threatening a strike, calling for Iran to surrender diplomatically.

The result was an extended Washington case of “will he or won’t he,” fueled in part by Mr. Trump’s own running commentary about his intentions toward Iran. Asked last week about ordering strikes, he told reporters that “I may do it. I may not do it,” adding proudly, “Nobody knows what I’m going to do.”

The revelation of the U.S. strikes on Sunday, code-named Midnight Hammer, left Iranians and much of the world struggling with basic questions: Was the president’s public hesitation to embrace military force actually a feint designed to lull Iran into complacency while the Pentagon prepared its assault? And if so, what does that mean for the prospect of future attempts to find a negotiated end to the fighting?

“There are concerns in the Middle East that the U.S. is now complicit in derailing the diplomatic efforts and that these were never authentic to begin with,” said Burcu Ozcelik, a senior research fellow in Middle East security at the Royal United Services Institute.