Nobody knows what the hell to make of North Korea. Is he insane? Do we laugh or cry? He can;t reach the USA, but he can reach Japan and South Korea. The one thing talked about behind the curtain is simple. War would be generally conventional. The nuks are there as a backup. If Russia invaded Europe, what good are nuks? Neither side would push the button so we are back to conventional warfare. That is the real reason to develop nuks. Not to use them, but to be able to use conventional forces fully.