Of all the foreign policy analysts in the world, I am probably in the bottom quartile. Or decile. So take this for what its worth.
We have heard rumors for months, even years, that the internal situation in North Korea is desperate, or more accurately even more FUBAR'd than usual. There have even been hints of open popular opposition to the government, definitely an unusual occurrence. I look at the attack on the South Korean ship in the context of domestic problems. This was Kim's "wag the dog" response. The classic totalitarian response to domestic problems is to seek out distracting foreign adventures. I think what we may be learning is that the domestic situation is even worse than has been supposed.