New Delhi, April 22 -- After U.S.-Israeli bombardment eliminated Iran's supreme leader and much of its top echelons, the Islamic Republic's leadership didn't fall apart - but negotiations to end the war offer a new test.

For decades, the supreme leader successfully managed several powerful factions, bringing to heel those who challenged his authority while listening to rival opinions. It's now unclear who wields that kind of authority over the collection of civilian figures and powerful generals from the paramilitary Revolutionary Guard who appear to be in charge.

They have found unity - for now - by taking a tough line. But disagreements over how much to concede in negotiations with the United States could reveal fault lines, as Pakist...