There was some question about what role the army may end up playing in all of this. My sense is that there has been a bit of a purge in the revolutionary guards, older, moderate officers have been pushed out and those loyal to Ahmedinejad promoted. It also seems like the Basij paramilitary has been strengthened, and made a vehicle for patronage by being given valuable franchises (including large construction contracts). Similar to the state of affairs in China, where certain enterprises are run by the army.
The patronage is coupled with something like selective economic warfare. If you inflate the economy, and then increase salaries for those loyal to you, you will impoverish your opponents and weaken them. Your opponents economic resources are weakened without your having to resort to something as crass as wholesale confiscation of their property. I’ve begun to think Ahmedinejad may be a lot more cunning than he is given credit for, and I don’t believe Khamenei is entirely in control. The army is a wild card, but some of the moderate forces have led the RG in the past and may still have friends there.
Another wild-card could very easily be the religious establishment. Their relationship with Khamenei may be less than collegial, apparently there has been some questioning of Khamenei’s religious training. If a group of influential clerics were to speak in favor of a run-off election, or against the repressive actions of the regime on Friday, that would have a huge impact.