http://en.wikipedia.org/wiki/Shankill_Butchers
Here are some pleasant characters from my childhood. They liked to kidnap Catholics, pull their teeth out with pliers, chop their faces up and then cut their throats. They killed over 30 innocents before the law caught up with them. It baffles me that you think all that was wrong with them was that they didn't have nukes.
If someone says, "Wait until I get a gun, so I can kill you." then that's an argument for not allowing them to have a gun. If someone says, "Wait until I get a gun, so I can defend myself from attackers." then you have no right to stop them. Likewise, you have no right to stop someone from owning nukes if they haven't made any threats. These "Shankill Butchers" obviously wouldn't get to own nukes. The only thing wrong with them was that they weren't given the same treatment after they were caught.
The Shankill butchers believed they were defending their community. Does that belief entitle them to nukes?