All up, I think we can generally understand why the Kim Dynasty government of North Korea (very similar to the Saudi Royal family government of saudi arabia in terms of human rights abuses and basic non-popularity) is a very paranoid entity. It borders Russia where Russian army forces are now increasing...and Russia certainly has invaded before...it borders China where the Chinese PLA is increasing its significant weaponry and soldier numbers along the Yalu River border, South Korea is unstable now and without a President, and the US is approaching it all with its nuclear arsenal in aggressive mode. That would make anyone paranoid. The history of what happened to Iraq and Libya and Afghanistan just recently is far too clear a lesson for what happens to a defined American strategic geo-poltical target that doesn't have Weapons of Mass Destruction. They are destroyed. They are not rebuilt. If the Kim Dynasty was removed by the USA's military forces from the air, with a ground push from the South, within an hour Russian land and sea and air forces would arrive in Pyongyang from the North, boots and all, as would China land, sea and air forces...would arrive from the East, with the USA pushing up from the South...and then you'd have the great face-off between America, China and Russia, eye to eye, all eyeing off the most valuable strategic piece of real estate on earth. The Great Tectonic Plate. I don't think anyone in their right mind wants that kind of massive world conflagration...except maybe the USA. Mr Kim Jong Un presents as a madman, but he knows the history of Korea very well..and he knows exactly where he lives. His main goal is to preserve himself and his dynasty, and the best way to do that is to quickly acquire as many weapons of mass destruction, including nuclear, gas etc as fast as possible. I believe he is very secure in his governance, unlike the US President, and will continue to rule quite badly for many decades to come, simply because, for the World, what does exist now is far better than that what would exist if he was destroyed. He is obviously very adept at mahjong.