[RandomGuy]

No offense, but this has all been going on for quite a while. See, for example, 1998's launch of a Taepodong-1 missile over Japan, 2006's failed launch of a Taepodong-2, or 2006's partially-successful nuclear test.

North Korea's government likes to be a provocateur, for the propaganda coups these events score at home, and the supposed bargaining-chip it gives them when dealing with other countries. Truth be told, all the saber-rattling really hurts their position, but with the politics of Kim Jong-il, the reasoning doesn't exactly have to be sound for a policy to be embraced. It's all about glorifying Dear Leader, and with total control over the national media, they create their own reality, while refusing to acknowledge that of the outside world.