Understand North Korea?

Comments on Andrei Lankov “Pyongyang strikes back”, 15/07/2009, http://www.eastasiaforum.org/2009/07/15/pyongyang-strikes-back/

While the arguments in this article are seemingly logic, I wonder whether there could be other explanations or reasons behind the North Korea's changing behaviour in the recent past.

It appears that there are still some unanswered questions.

I had thought it was the fault of the North's political leaderships that caused all this, but then I encountered the comments by Richard Broinowski that shed some different light, suggesting that some other parties also contributed to that (see http://www.eastasiaforum.org/2009/07/05/obamas-north-korea-policy-and-the-june-15-south-north-joint-declaration/#comments).

The fear of the potential destabilisation of a rich South on the North sounds attractive. But didn’t the leadership think about that during the relatively relaxed period in the first place?

Further, how the North leaderships think strategically about the future of the North? Do they really think they can hide the different realities between the two Koreas forever?