This is saber-rattling, attention-getting behavior from an insular, paranoid regime. It isn't just Kim Jong Il (who is, in fact, ill). The structure is very Stalinist/Maoist/Nazist "cult of personality" driven, but more importantly, totalitarian, and there are other less-than-stable militarists in charge below Kim. Personally, I favor using it as an opportunity to test our interception technology rather than any aggressive action directly against the mainland of North Korea. They can't afford very many such efforts, and the more they try, the poorer their country gets and the closer to collapse. In the grander scheme, there are a number of unstable pseudo-regimes that should be demilitarized. The problem is, "who gets to pick" which ones they are?