You're talking about past history, like in the 50's.  There haven't been any real military action since then and the North didn't have anything resembling nuclear devices.  I can't even remember the last time the U.S. was involved in any real high level talks with the North - none in probably the last 40+ years.  The U.S. NEVER had any high level talks with the North about nuclear weapons.  You should be asking yourself where have you been?  Remember I said "high level" talks, not lackey representatives from each country.