SMOKING GUN
It WAS about the oil:

Let's look at it simply. The most important difference between North Korea and Iraq is that economically, we just had no choice in Iraq. The country swims on a sea of oil. -- Deputy Defense Secretary Paul Wolfowitz, quoted in today's Guardian.

I'm sure that makes Saudi Arabia, Venezuela, Mexico, Nigeria and other oil-producing countries feel really secure right now. Wolfowitz is certifiably insane, and he's running (ruining) our foreign policy.