If by then they haven't already had their nuclear program destroyed (via covert US operations) the program will be destroyed via US covert operations.

No news of this will leak inside or outside of North Korea. If it does leak, the government of NK will fall and a civil war within NK will ensue. This civil war will spill over into SK as the countering forces within NK will attempt to blame the chaos on SK and the United States.

Within 6 months of SK entering the expanded conflict, and with US indirect backing, SK will declare victory as only a few Communist rebels will remain in the North and their actions will be completely uncoordinated.

China will welcome the change. Japan will welcome the change. The United States will welcome the change. The United Nations will attack the United States and demand war reparations.

Scott

(really this is the way it will happen...Unless NK launches a first strike...Then NK will glow in the dark for the next 116 years...)