@FreeDuck,
If Mousavi was thought to be any threat to the continued reign of the Mullahs, he would not have been allowed to run for the presidency.
His history as the former Prime Minister certainly doesn't suggest a moderate reformist and Obama was not off base when he questioned whether there was any significant difference between Mousavi and Ahmendinijad.
It's certainly possible that during his 20 years in the Iranian political desert he had a radical change of heart and mind, but if so, he did a good job hiding it from the Mullahs once he returned.
If he had won the election instead of Ahmendidjad I don't believe we would have seen a significant change in the government which is why it was so stupid for the regime to rig the election. If Mousavi has won, their control of Iran would not have measurably diminished and a large percentage of the population that is reform minded would have been mollified.
One of the reason it is impossible to predict world events with any certainty. Throughout the ages significant people have made the illogical decision and huge changes result.
Pure speculation, but as something of an insider perhaps he saw that there were schisms in the regime that could be exploited and the dramatic reaction to the election results offered him a once in a lifetime opportunity to exploit those schisms and come out truly on top. A pretty ballsy move if the case.
In the unlikely event that there is a successful revolution and Mousavi ends up as the leader of the new government, there's virtually no chance that he will reproduce the oppressive environment. Such a revolution will have to have the support of a sizeable faction of the military. Students, women's right activists and intellectuals, no matter how well armed with guns and fervor are not going to defeat the Baseej and The Revolutionary Guard.
However, should they obtain the support they need from the military, and overthrow the regime; they will have accomplished quite a feat. They will certainly not be prepared to allow Mousavi the Tyrant fill the vacuum. He will have to become Mousavi the Democrat or the victorious people will can his ass in a minute.
A post-revolution military coup is perhaps another story.
Unfortunately, I think all post-revolution speculation is moot. It's a terrible shame.
We're brought up, at least in this country, to believe that people taking a stand for what is right and displaying uncommon bravery to obtain it will succeed. Sometime it does happen, but very often it does not, and when it does, and we look more deeply into the hows and whys we find a far more complex and far less pristine situation that we wanted to imagine.