Almost 40 years ago I was stationed in Korea and Kim's father spouted the same threats, minus nukes of course, to invade S. Korea, and destroy the "Yanks"  Many a day I heard the same lame "We are only 3 minutes MIG fighter time from being bombed.  What has changed? nothing....well actually there will be more peace because now N.Korea is a member of the "MAD" club, "Mutually Assured Destruction".  However in N. Koreas case, we won't be completely destroyed but N.Korea will glow for a thousand years.