They are far more sophisticated than many here are crediting them...
They get the bomb and you have to talk & concede. That is the real fear.
Ultimately its a diplomatic advantage/issue.
Pretty much as I see it as lets face it Pakistan has the bomb with Saudi cash and they a lot more unstable than Iran.
Issue the Western powers have with Iran is that it refuses to co tow to the West despite the Western powers attempt at destruction be it Iraqi invasion and previous coups.