I'm going with a nation that wasn't burned by nuclear fire, which means that they'll probably be the leaders in terms of technology, because they have the more recent old-world stuff. And because they weren't blown up, those that were seeking civilization and a new command structure to follow would find them, though there would be disorganization, resentment, etc., because of the war.
Great idea! I happen to think the same thing. We could always have our nations close by, working together?