The irony of two former colleagues now competing for power over the expiring corpse of the Islamic Republic that they created with such grandiose expectations is lost on no one. The important subtext, however, is that these two understand very well what they are doing. They know how a revolt can be turned into a revolution. They also know they have everything to lose. The shared consciousness of high stakes has until now prevented an all-out political confrontation between rival factions in the elite. That may help explain why the rahbar and the Revolutionary Guards were so reckless in their insolent contempt of the reformers and the public. They may have believed that no one would dare take it to this level.

Now that it has arrived at this point, both protagonists are faced with decisions of unprecedented gravity. There has been nothing like this in the 30-year history of the Islamic Republic, and today there is no Khomeini father figure to moderate and mediate among the warring factions. They must improvise in conditions of severe uncertainty. If anyone tells you that they know how this will turn out, treat their words with the same regard you would have for any fortune teller peering into a crystal ball.

For the United States, the watchword should be: Do no harm.