Kim Jong-un is a cruel dictator but his actions are rational and aimed at staying in power.
Like his grandfather and father, Kim presumably believes that nuclear weapons are the best guarantor of his regimes survival. Its a realistic judgment.
The Norths nuclear program has given it international bargaining power and made the regime an impossibly hard target.
Libyas Muammar Gaddafi decided to abandon his ambitious nuclear weapons program in 2003. The North Korean regime will conclude that was a bad move given the willingness of the West to help bring the Libyan regime down in 2011.
It may be that Kim Jong-un hopes the test will incline Barack Obama to open negotiations with North Korea in the same way the US did with Iran. In his apparent pursuit of the United Nations secretary-generals job Kevin Rudd has said an opportunity was lost in not opening negotiations with the North after the Iran nuclear deal was concluded a few months ago.
Most likely we will see an attempt at stronger sanctions and louder rhetoric condemning the North. But there is little that can really be done to halt their nuclear program from developing further.
