Nuclear weapons barely change the equation. The best estimate is that North Korea could begin firing around 10,000 artillery shells per minute into densely populated suburbs areas around Seoul on a moment's notice. Even if through some masterful and historic level of effort we managed to shut down those artillery bombardments or evacuate the targeted areas in a mere half an hour that still leaves hundreds of thousands of civilians dead and huge numbers of homes and businesses destroyed. It would be a destruction on the scale of a natural disaster such as the earthquake off Japan earlier this year. Add in the very real possibility of North Korean nuclear weapons landing on Seoul, Tokyo, Taiwan or maybe even the US mainland and that starts focusing your thinking about how worthwhile it would have to be to depose the North Korean regime.