In a performance that may be remembered for years to come, Ayatollah Khamenei put on a show at this morning's prayers. The ayatollah said that not only were the elections legitimate, but that the "street challenge is not acceptable." He all but threatened Mousavi directly, saying: "I call on all to put an end to this method. ... If they don't, they will be held responsible for the chaos and the consequences."

What of the challenge to the regime's authority? "Some may imagine that street action will create political leverage against the system and force the authorities to give in to threats. No, this is wrong," Khamenei said.

And who is to blame for this unrest? America and the Zionists, of course.

The "evil media" belonging to "Zionists" is trying to draw into question Ahmadinejad's overwhelming victory, Khameini said. The 60-plus percent of the vote Ahmadinejad supposedly got was not suspicious, Khameini argued, but instead a sign of convincing victory.

"Some of our enemies in different parts of the world intended to depict this absolute victory, this definitive victory, as a doubtful victory...It is your victory. They cannot manipulate it."

Four observations:

First, keep an eye on the Revolutionary Guard, which has promised to stomp the opposition. We can only speculate on what the IRGC will be ordered to do at this point. There are unsubstantiated reports that the IRGC may be ready to deploy. Some reports suggest that IRGC commanders who are sympathetic to the protesters have been arrested. And the ayatollah's threats seem to indicate that he is preparing to blame Mousavi for any bloodshed. That is, the ayatollah has created a pretext for not only blaming the opposition for any escalation, but also created a storyline he can use to frame any crackdown on Mousavi himself.

Thus far, the violence has been mainly perpetrated by the IRGC's Basij militia. The Basij has beaten protesters, and reportedly killed some. But the Basij has focused largely on stealth techniques, including hunting down and arresting protesters at night, when there is less scrutiny of their actions. If the IRGC's professionals are deployed, then the violence could quickly escalate.

Second, the ayatollah and Ahmadinejad's comments may very well antagonize the protesters further. It was not wise to openly insult the hundreds of thousands of protesters taking to the streets, yet that is exactly what the regime's leaders did. This was hardly a "rational" move by the regime's hardliners.

Third, the ball is now in Mousavi's court. Make no mistake about it, he has been warned. If Mousavi continues to lead the protests, then the ayatollah and his forces will hold him accountable. Will Mousavi back down? It does not appear he will, having rejected the ayatollah's offer to attend the Friday morning prayers. (That offer was undoubtedly intended to get Mousavi to give in.) But if Mousavi presses on, what is his gameplan for handling the violence that may be headed his way?

Fourth, now, today, is another opporunity for President Obama to speak. Mousavi has been threatened, as have the thousands of protesters. The ayatollah offered no conciliatory language for the protesters or the West. There was no talk of redoing the stolen election, or giving Mousavi a seat at the table. Obama has gone out of his way not to "meddle" in this affair, thinking that America's "meddling" may compromise efforts to negotiate with the Iranian regime going forward.

What has been the reward for America sidelining itself? More condemnations from the regime that Obama wants to negotiate with. That same regime may be on the verge of an even more violent convulsion.