That's assuming that NK is just building the deterrent to stay in power. Another possibility is that they would seek to increase their power against other, non

That's assuming that NK is just building the deterrent to stay in power. Another possibility is that they would seek to increase their power against other, non-nuclear armed nations. Many of NK's historical actions such as kidnapping foreign citizens [0] or the abominable treatment of prisoners like Otto Warmbier cannot be explained simply by a rational desire for regime survival. We don't really know what their end game is.