How come nobody seems to think about neighbouring Pakistan in this context, also a nuke power? Religion is stronger than politics, and in a huge area where nationhood is largely an arbitrary, external construct, the ramifications are more like taking on the Mafia than a specific country.
In the end, the difference has always been that where the West thinks it's fighting a political war, the other side is seeing it as an existential, religious clash of civilizations.
The deal-that-Alan-says-is-not-a-deal was supposed to bring counter benefits to Iran in terms of investment and trade: what did it see? Next to nada. A few little French capillaries, then Amen. But it did see stronger hatred, more vitriolic language and, ultimately, the dismemberment of the thin ray of hope both sides could have used, given some patience and slack. There is the presumed attempt to bring some countries back into the wider world, but the moment there's even a chance, bam! there goes the straight left. It often seems those "pariahs" are actually an essential part of the trade paradigm: remove them, and waddya got? You got no reason to make or buy weapons and have vast armed forces... that will never do!
Some people speak of compromise when what they mean is absolute defeat and humiliation of the other side. As has been posed here before: a man with nothing left to lose is one dangerous cat.