You gotta be kidding me. NK is the one place where war should truly be avoided at all costs. It's not a question of winning, but a matter of how they'd lash out in the face of certain defeat. Seoul and its approx 20+ million people are just a hop, skip and a jump away from the DMZ. Busan and Daegu are within firing range as well, not to mention several other large cities in SK. It would be a disaster from a civilian casualty standpoint. Unless there is a way to take down the entire apparatus simultaneously, you don't do it. NK will implode eventually. Let them talk shit like they always do. They aren't assassinating SK's first ladies anymore or launching raids on the Blue House. They aren't even blowing up people at airports or in airplanes, even if they did kill that defector. Absent some kind of appalling provocation on their part, there is no reason to preemtively fight.