Maybe a poor analogy but I can't think of anything to compare with the unthinkable that you think.

The reason you're having trouble making an analogy is because you've been subtly influenced by the strategy of Iran. It's almost like a form of "Finlandization". Ahmadinejad's M.O. is fear and manipulation - just the notion that he "might" build a nuclear weapon gives him the ability to manipulate people into thinking that trying to stand up to them would have dire consequences. Guess what...Ahmadinejad wins.