What I wonder about is all of the technologies that go into ICBM's with nuclear weapons. My layman's guess is that there is active support and collaboration of the NK nuclear program from outside. North Korea is a headache for the US and other western powers, one more thing to consume policy bandwidth and military preparedness. This would seem to be in the interests of China and Russia, and perhaps others. I don't worry too much about the threats that periodically emanate from North Korean; if they start to exceed their utility from the perspective of China and Russia, the needed resources to maintain a viable nuclear program can be quickly shut off. I do hope that I will live to see a "1989" moment in which the North Korean regime is overthrown, and relegated to a horrible and sad footnote in human history.