Hamidreza Taraghi, a political analyst close to Ayatollah Khamenei, said it should not be surprising that Iran’s establishment has closed ranks behind the negotiators and the talks.

“Wherever Foreign Minister Zarif goes to explain about the negotiations, his arguments are convincing and accepted,” he said. “Of course, we worry about some details, but they will be hammered out and solved, we are sure.”

On Tuesday, Mr. Zarif earned glowing praise after he paid a visit to Parliament to describe the nuclear framework and answer lawmakers’ questions.