well, that's not the case about ahmadinejad and the rest of them. they are as sane as every other politician when it comes to power and money, and they definitely won't do something stupid because of their faith, but they may do stupid mistakes like any other dictatorship through the history. since they are under pressure from inside and outside, it's not totally irrational to start an erosive war and wipe out inside opposition silently. at least, it's not so unexpected from them to execute such plan if the inside opposition becomes a serious threat to their existence, which is gonna happen soon.
I know there was a difference between your point and his, which I'd attempted to emphasize. I don't think your own claim is true either, but it's not as obviously wrong as his was and I don't know enough about it to really address it with the attention it merits.
Israel has a defensive missile system.
"He who does not think himself worth saving from poverty and ignorance by his own efforts, will hardly be thought worth the efforts of anybody else." -- Frederick Douglass, Self-Made Men (1872)
Let's see...we decide to withdraw a planned missile and listening station in Eastern Europe....and the Iranians immediately test their medium range ballistic missiles that can easily reach Eastern Europe.
Obama is a genius.
We've -never- been in a better position to go to war with Iran.
That said, there's absolutely no support for the argument that any such war would necessitate a general invasion of Iran.
Additionally, those who would make the argument that they will "use the rest of theirs on us" would have to show they even had more warheads, and show there was a delivery system capable of reaching the United States. Given that Iran does not currently possess such a delivery system, all they could do from a nuclear standpoint is use a warhead on US troops stationed in the region. I have little doubt that should this occur, anyone would hesitate to respond with overwhelming nuclear superiority.
Perhaps someone would make that argument, but they would look like an idiot doing it in my view.