There are lost counties you open your arms for and bring back into the fold.
Then there are rabid dogs you just simply put down.
North Korea is absolutely the latter. A war should be expected and prepared for. And with long term planning with global partners. South Korea especially needs to be prepared, and figure out how to empty Seoul long before the first nuke is fired. We're talking urban planning and development to depopulate the city as much as possible. We're talking slowly, over the course of years. Because a nuclear war may not be today, it may not be tomorrow, but with these crazy SOBs you have to plan for the worst.