I don't pretend to have a sophisticated grasp on the complexities of Iranian politics and society, but it's worth noting that Ahmadinejad had support outside Iran too. To wit, Daniel Pipes:
while my heart goes out to the many Iranians who desperately want the vile Ahmadinejad out of power, my head tells me it's best that he remain in office. When Mohammed Khatami was president, his sweet words lulled many people into complacency, even as the nuclear weapons program developed on his watch. If the patterns remain unchanged, better to have a bellicose, apocalyptic, in-your-face Ahmadinejad who scares the world than a sweet-talking Mousavi who again lulls it to sleep, even as thousands of centrifuges whir away.
need one another
Now, in Persia, it might well be that a "new Iran" would want to pursue its nuclear ambitions and a reformed Iran would not necessarily be friendly to the west but those are different matters entirely. And, of course, it's also the case that a President Moussavi wouldn't have controlled nuclear policy either. Nonetheless, it seems a bit tough on the poor Iranian people that their hopes for change should be dismissed by foreigners in this fashion. Daniel Pipes' heart may "go out" to the Iranians but given the apparent tinyness of his heart what good can that do them?
*Of course, just because they were wrong then, doesn't mean they have to be now. Still...