In a vacuum, North Korea is not the most dangerous place on earth for about 1000 reasons many of which were explicated in this book written many years ago (Waltz makes a very effective summary of your arguments above):
Unfortunately, we don’t live in a vacuum and the problem isn’t Kim Jong-Un it is the unpredictability and irrationality of the current US leadership.
Anyway, mostly agree. But, I should probably point out that all of this is easy for people in the United States to say. I suspect it is a bit more on the tense side if you live in South Korea :(.
