I am not concerned. I think this has been around and in the hands of far more dangerous regimes already. If they tried to use a nuke then they wouldnt survive. NK is all about survival. Would they fight back in self defence? Of course. All nations would do that. Hopefully it would never come to that. The lesson of Iraq was that you should have nukes. In an ideal world you would be nuke free but I understand why a nation would desire them in the current climate.