In this era, the word could more or less be won by the Navy and Air Force. We could, at least, diminish their forces to a point where they would no longer be much of a threat- foreign SOF type units and an insurgency wouldn't be much of a threat if we didn't want it to be (as in, we don't land ground forces and try to 'rebuild' their savage nation).
North Korean ground forces wouldn't be of much use without air or armor support. Massed ground troops (Korean War style) would be cut to pieces with modern technology. I don't know what type of SOF forces N Korea has, but without infantry, artillery, and air support- I doubt they are much of a worry for the ROK. Hell, the best SOF forces in the world are no match for comparable conventional infantry without support (ODA vs. 82nd Airborne rifle platoon would probably result in an epic failure).