I put this to a fellow student in my IR class yesterday: If the worst bully you know were to threaten to take away from you your intimate partner - perhaps your girlfriend, perhaps your wife and kids when you have them - would you be justified in raping the bully's young daughter? If it would be immoral to rape the bad guy's innocent daughter, no matter how bad he is, it's (almost) equally immoral to threaten to do so. It's the same with nuclear weapons and WMDs: no matter what the bullies and the bad guys do, that's no excuse for retaliation, especially a form of retribution or vendetta that would lead to mutually assured destruction. Nor is it an excuse for arming oneself against an enemy as a veiled threat of counter-attack.

Your thoughts?