OK, this should reassure you. There are:
(1) Nuclear Subs off the coast of NK-they can deliver a nuclear warhead right into NK - POOF! No more problem
(2) Recently there have been aircraft carriers moved into position on training missions. These aircraft carriers have nukes onboard - POOF! No more problem
If our goverment sees any inkling of a nuke headed our way BEFORE one is launched, NK is toast. By the way, did you know, there are little nukes and big nukes? They're measured by megatons of force released during the blast. I hope no government ever needs to detonate one, but if some loon decides to do it, there'll be hell to pay.