In April 2003, North Korea drew the obvious conclusion from the US and British aggression against Iraq. The war showed, it commented at the time, "that to allow disarmament through inspections does not help avert a war, but rather sparks it". Only "a tremendous military deterrent force", it stated with unavoidable logic, could prevent attacks on states the world's only superpower was determined to bring to heel.
The lesson could not be clearer. Of Bush's "axis" states, Iraq, which had no weapons of mass destruction, was invaded and occupied; North Korea, which already had some nuclear capacity, was left untouched and is most unlikely to be attacked in future; while Iran, which has yet to develop a nuclear capability, is still threatened with aggression by both the US and Israel.
Obama has yet to teach the world a new lesson. Only when he does, will we find out the true nature of the regimes we like to sneer at. Until the U.S. behaves in a way that teaches a new lesson, we have little reason to assume regimes seeking nukes are irrational or evil.