Conventional wisdom about Iran has long been that the nation's senior Muslim cleric would have the final say on domestic and foreign policies, no matter who won the June 12 presidential election.
But that calculus has been challenged with the explosion of protests in the streets. Iran analysts say Supreme Leader Ayatollah Ali Khamenei could well emerge diminished in stature because of his too-quick confirmation of victory of incumbent President Mahmoud Ahmadinejad -- an outcome now discredited by allegations of fraud.
"Whatever happens, Khamenei comes out looking bad," said Judith Yaphe, an Iran specialist at the National Defense University.
"It's a turning point," she added. "There has been nothing like this since the  revolution."
She and other analysts sketch three scenarios, none of which is friendly to Ayatollah Khamenei.
- The first and most likely scenario is that an investigation the ayatollah ordered Monday into the election results by the Guardian Council, a body largely appointed by the supreme leader, grants additional votes to Mir Hossein Mousavi and other challengers, but the incumbent still wins. Protests eventually peter out, but supporters of Mr. Mousavi, who have risked their lives to come into the streets, still feel cheated, and the situation remains unstable.
- A second scenario has the government cracking down on protesters as China did in Tiananmen Square in 1989. In that case, Ayatollah Khamenei remains in power - but "at a huge cost" to his legitimacy, Ms. Yaphe said.
- In a third scenario, the government concedes that the election results were doctored and Mr. Mousavi becomes president, in which case Iran will in effect have gone through another popular revolution.