North Korea is a country (technologically speaking) stuck in the 1950's. Kim Jong Un is an attention seeker trying to establish himself as a credible threat other than Il's pudgy teenage boy. If for some strange reason they went through with launching a nuke, it wouldn't be North Korea you should be afraid of. It'd be possible allies like China. But even then, I think China realizes how futile it would be to make America an open enemy. After all, the profit they make from America is unbelievable. Even if Americans were to play into that whole "Buy USA" fad, it would be a drop in the bucket. In the same way people combine their debt by taking one credit card and paying off all the other cards (that way it's on a single card); the American government chose to do the same with allowing China to "purchase debt" -- thus solely owing the purchased amount to China. As of last year, China owned 1.2 trillion dollars of America's debt.
At any time they wish, they could request payment immediately and shut off all exports to America. The price of simple goods would skyrocket -- similar to the universal price hike during Reagan's presidency with the last "Buy American!" fad.
Pretty crazy.
I'm not sure if you guys are fans of Vice, but you should check out this series. It's crazy, hilarious and very eye opening. Especially the last few videos when the crew encounter Russian mobsters who take them into the labor camps and nearly get shot up.
Or this one from Vice where they actually sneak into North Korea. Again, it has both humor and eye opening appeal.
Vice rules. If you want any other good ones from them, ask. I have a handle on nearly all the best videos (because I've watched nearly all of them, hahahah!)