Gideon Rachman points out in Financial Times that the doctrine of mutually assured destruction (MAD), employed by the West in nuclear confrontations, assumes a rational adversary:
In many respects, North Korea has replicated some of the very worst features of Maoist China: the isolation from the outside world, the labour camps, the cult of personality and the willingness to tolerate mass starvation at home. The latter is particularly chilling, when one remembers that nuclear deterrence is meant to rely on an unwillingness to accept the death of millions of your compatriots.
Read more at North Korea tests the limits of a MAD world | Business Spectator.