Actually, India and Pakistan seem to be relatively sane about the matter. When one nation tested nuclear weapons, the other nation didn’t respond with a nuclear strike, they simply did a test of their own, as if to say, “We’ve got the same toys as you, if you really want to play, then it’s going to cost you.” The US and the USSR never went after one another in an overt military manner after the introduction of nuclear weapons. Instead they fought proxy wars, and engaged in “diplomatic actions” like the blockade of Cuba. Reason being that the nations in question were led by semi-rational human beings. I’m not sure that Iran’s led by rational folks, NK’s certainly not, and the sanity of Bush & Co. is debateable.
I’d like to say that the best course of action is for the US to not poke Iran with pointed sticks, and dump billions of dollars into developing technologies which reduce the need for oil, since that will cut the money flowing into all the oil rich nations (many of whom seem to have the annoying habit of giving money to nutjobs like Bin Laden), but if the money stops flowing into places like Iran, then I’m afraid that it’s going to make it easier for nutjobs like Bin Laden to gain followers, and sooner or later one of them is going to point out that they’re starving and they have nuclear weapons, so that since they’re going to die anyway, why not take as many of the infidels with them as they can?