The reason the US government publically gives for moves against Iraq and Saddam Hussain is that Iraq is trying to develop "weapons of mass destruction" - nuclear weapons. Developing nuclear weapons is obviously a big no-no, which is why Iraq had to have the UN weapons inspectors in.
If this is the real reason (which I really doubt that it is) then why didn't America send the boys in when India or Pakistan went nuclear? And what goes on in the minds of these government folk that they can simultaneous believe that developing nuclear weapons is such a venial sin that we ought to go and assassinate the President, but the fact that the US already has nuclear weapons is good and proper? Obviously it's a flimsy excuse, but why has nobody called them up on it?