In response to this, I should like to note three things.
First, it is entirely possible that Persian nationalism, in the event of a collapse of the Mullarchy, will require constraints, both by the nature of the case, and in virtue of the fact that, well, we're talking about Central Asia, the womb of horrors. The probability of this would decline, I think, in large part because a large plurality of Iranians have little sympathy for the Islamic regime and its more sanguinary aspirations. In any event, I believe that a nuclear Persia can be deterred. I don't foresee a new era of national martyrdom.
Second, whether one deems it sympathy or 'seeing things from the other guy's perspective', this habit of thought is integral to effective foreign policy-making. Absent this capacity, one cannot effectively anticipate the reactions of the Other, and absent such anticipations, one cannot assess prudentially the probable consequences of various courses of action. We have already witnessed the consequences of this purblind willfulness in Iraq: we will be greeted as liberators, and Iraqis care nothing for tribe, religion and whatever by comparison to Democracy! Whiskey! Sexy! In Persia, were we to somehow engineer or encourage a relatively peaceful transition from the Islamic Republic to.. something else (the Shah? - I cannot predict), we would be swiftly disappointed if we expected the Persians to accept American overlordship, quite apart from the factor of Islam. Their own patriotic sentiments would never permit it.
And that leads to the third point, which is that, for Persians, accession to the nuclear club is perceived as a badge of national honour, as well as a sign of regional status. Beyond that, Peak Oil is real, and if Americans really believe that Persians are going to accept "lights out!" as a legitimate option, merely because America says that Persian ambitions are unacceptable, whether Islamic or not, well, then Americans are nuts. This would represent a massive failure to understand and predict the reactions of the Other, a massive failure of prudential reason. And, off at the margins, is it even licit to compel another society to revert to premodernity, with all of what that would entail? I'd not like to see, let alone make, that argument.