In my opinion, the tendency for the small countries to develop WMD calls for a policy of preemption, rather than simply defense. The US must change the rules of the game such that nuclear weapons become not a guarantee against attack, but rather a guarantee that the regime will be attacked.
The nuclear club must be closed to new membership, and this must be enforced by the US military. There's no other way. It's simply too dangerous for us to not hold this policy. North Korea is a perfect example of what happens if we are negligent in stopping proliferation.
Unfortunately, the world is a harsh place, and harsh measures may need to be taken to ensure our security.
And the answer to the question of who are we to decide who gets nuclear weapons is that we are the strongest, wealthiest, and freest country in the world. We are also the most likely target of these weapons and we are the ones who inevitably go in to clean up the messes caused by these little Hitlers. I prefer to do the cleanup when the job is small, rather than waiting for disasterous consequences.
Seems that's Bush's point. Would that more sheeple understood it.