On top of ^^^ Rumblood's accurate description of the American drive to kick ass and take no prisoners, he's forgetting two important things:
1. The vast majority of his widely publicized test rockets fail miserably and crash. And where exactly does that nuke fall? Near enough to North Korea to make it amusing (were it not for the, you know... South Koreans and other cool stuff nearby).
2. China won't let him. Alas, the era of the golden rice bowl doesn't like it when you destroy their assets most critical trading partner.
Do these matter? Who knows. That's why Kim Jong Il and his rising doughboy son are my fave dictators. Seriously, even Smoothrich can't match this level of crazy dictator (try ever as hard as he may).