Originally Posted by Fidei Defensor

I disagree. For one, I think you and others who assume "obliteration" in response may be overestimating the response. I don't assume that there would be an obliteration of Iran in response to a terrorist-delivered nuclear or radioactive attack on the U.S., and I also doubt that the response would be immediate.

In the wake of such an attack, I would first expect hemming and hawing over the responsibility. If the material can be traced to its source, that will take time. Then, assuming a link to Iran, there will be denials of culpability and impassioned defenses of Iran, likely including absence of proof that Iran deliberatively provided the material to terrorists and/or that it intended such an attack. I would also expect part of the defense to include a line of reasoning that the attack was provoked by the United States.

Finally, while there would certainly be a thirst for blood among many Americans, many simply will not want to kill millions of innocent people in retaliation. I would not take a catastrophic response as a given at all, and if the Iranian leadership understands Americans as well as I do, they won't either.