Iran? Wow, What Won't These Geniuses Think Of?
The thing with Iran is that there is a strong internal reform movement there. Sure they've had temporary setbacks in the last election cycle, but it's only the gerrymandering of the hardliners in certain unelected positions that keep the reformers from holding the balance of power. The fact is, I don't think it's unreasonable at all to expect that the reformist element will continue to be ascendent in Iranian society. The way to strengthen the hardliners would be to introduce a foreign threat. Look what happened in the US post-9/11/01, everyone cleaved to a religious fundamentalist and his hardline conservative henchmen. A foreign threat to Iran will produce the same result.
Of course this would problematic if anyone in the US was actually interested in the spread of democracy. Fortunately, no one is actually interested in that, instead they want pliable client states. The appearance of democracy might play well for the folks at home, but it's far from essential for the aims of Wolfowitz et al. True democracy is something that I don't think the Americans actually wanted. When the citizens of Iraq rose up in 1991 they took control of 15 of the 19 Iraqi provinces, yet the US didn't help then. Why? Because this was a legitmate broad-based uprising, not some posturing by the Allawi-Chalabi axis of avarice. The Americans made the conscious decision that they preferred the devil they knew (Saddam) over the possibility of Iraqis actually choosing their own destiny. They waited instead until well after the popular uprising was crushed and but a distant memory to act themselves. This way, the US ensured that they could dictate the shape of the new Iraqi "democracy."
What they want for Iran is the same thing, a pliable client state that is nominally democratic. If there is any doubt, remember that the CIA already deposed a truly democratic leader in Iran once (in the 1950s) and installed a dictator (The Shah). So if they are stupid enough to do another invasion, I think it is reasonable to expect the result to be equally bad.