Tomorrow is a big day, maybe I'll get killed tomorrow! - I will participate in the demonstrations tomorrow. Maybe they will turn violent. Maybe I will be one of the people who is going to get killed. I'm listening to all my favorite music. I even want to dance to a few songs. I always wanted to have very narrow eyebrows. Yes, maybe I will go to the salon before I go tomorrow! - A blogger in Tehran 6/20/09

After Supreme Leader Ayatollah Khamenei's speech yesterday warning that further demonstrations would be viewed harshly, initial reaction from the Mousavi camp was that "no demonstrations were planned for Saturday or Sunday" and Mousavi himself would not be speaking.

Then, last night, word began to be passed via Twitter and the newly restored access to Facebook and other social networking avenues, that Hossein Mousavi was calling on his supporters to assemble in downtown Tehran for a demonstration at 4:00 pm local time.

Expect the crowds to be huge. Should we also expect bloodshed?

Mousavi is rolling the dice that the regime will not do what the Shah didn't have the stomach for 30 years ago - fire into masses of people demonstrating against the goverment, making the streets literally run red with blood. This time, it won't be the ill-disciplined Basij firing at the odd protestor in an unplanned response to a mob attacking their headquarters as was the case with the bloodletting earlier in the week. This time, it will be a coldly calculating, deliberately planned massacre - Tienanmen Square on steroids.

In 1989, the Communist Chinese only had a couple of thousand die hards in the square as targets. Most of the rest of the protestors vacated the square long before the army - conscripts from the provinces who were told they were putting down a "counterrevolution" - moved in and mowed down the kids who believed up to the last minute their government wouldn't murder them.

This will be much different if the regime delivers on its veiled threats - which makes the determination of the protestors all the more remarkable.

I find it of unknown significance that the regime has re-established at least some communications networks. Evidently, Facebook, and SMS texting are no longer being blocked. The call for the march originated on Mousavi's Facebook page. It is impossible to reasonably speculate why the regime would make it easier for the demonstrators to organize at this crucial hour. Are the protestors being assisted by a faction that wants to see Ahmadinejad/Khamenei fall? Are the authorities trying to create as many targets as possible, smoking out regime opponents so that they can arrest as many of them as possible? It may be important, it may not be. We may never know.

Meanwhile, some analysts here and abroad believe that the Supreme Leader miscalculated if he thought his speech would dampen enthusiasm for reform:

Khamenei, 69, appeared to have miscalculated if he thought he could cow the opposition with his tough speech, said Mohammad Sahimi, an Iranian-American professor of chemical engineering at the University of Southern California and political analyst.

"I think he has polarized the society far more than it was because he made clear what his preference is and where he stands and who he supports," Sahimi said. The opposition is "openly defying this guy. In the short run, it may it lead to violence."