Nothing short of an actual Iranian nuclear attack on US soil would ever result in the kind of outcome you describe and they are nowhere near having that capability.
If whoever is in office would be stupid enough to call for such a thing the backlash against the US would be massive and not just from the Moslem world. Our economy would be in shambles after that due to a catastrophic energy crisis. Our own citizenry would be rioting both for the action itself and the subsequent decline of our social system.
Your improbable scenario is would you would do if you want the children of previously middle income parents to literally starve on the streets of our suburbs.
Luckily like you said, that would never happen. Iran will never invade Iraq because as buddy buddy as they are now with Sadr he would turn on them almost instantly. Iraq is actually much more nationalistic then people give them credit for and there still are very deep wounds from the previous war.
If anything, Iran attacking the US in Iraq would only strengthen what is turning out to be a very delicate alliance between Malaki and the US. Right now Iraq is balking at Bush wanting to install a couple dozen military bases inside Iraq and the very second an Iranian tank crossed the border there would be no more objections to the US proposal. They would also rally the rest of our allies back into the fight.
That is not to mention the fact that our conventional forces in Iraq alone would be enough to utterly decimate any kind of standard Iranian advance.
Iran's strong position right now is to simply play on our absolute unilateral ineptitude in Iraq. Right now the world is on their side because the world realizes that currently they pose no global threat. Emphasis on currently. Even our own intelligence points to that fact. So Iran will very much be content to score geopolitical points and continue to hand bullets to insurgents under the table to keep the US paying for its folly.
Of course, biblical creationists are committed to belief in God's written Word, the Bible, which forbids bearing false witness; --AIG (lest they forget)
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