Yeah, but who decided that other countries shouldn't have them?

Well, the world decided in 1968 that countries that did not already have nuclear weapons by that arbitrary date would be denied them in the Nonproliferation Treaty (which went into effect in 1970). India, who was about a year away from going nuclear, was left out of the nuclear powers. They willingly decided not to go nuclear and furthermore decided that they would not sign unless everybody gave up nuclear weapons. Almost every other country in the world signed the agreement, including Iraq. Iraq also signed the Biological Weapons Convention, agreeing not to develop biological weapons. Almost every country in the world signed the Chemical Weapons Convention except for 5 countries in the Middle East, one of which was Iraq.

So, in a way, the world, including Iraq themselves, decided that Iraq shouldn't have nuclear or biological weapons. Trafficking of chemical and biological weapons was limited and their development similarly limited. The world took on the responsibility of policing these agreements and enforcing them on every country.

I just don't know that it's ethical or moral for the US to say that other countries can't have them when it does.

And I really don't understand why the U.S. can have nuclear weapons when they won't let Timothy McVeigh have his? Why is it moral for us to have them and not Mullah Omar?

Well, somebody has to have the weapons to serve as a deterrent. All of the allies of the United States are protected under our nuclear umbrella. A handful of our allies, including the British, also have their own weapons (although some, like Italy, would have prevented any U.S. warheads being fired from their country). This has largely helped to dissuade war. Who would have thought after WWII that every country in Europe could essentially disarm and be free from conflict for the first time in their history? Likewise, how likely do you think it would have been for the entire world, including the diametrically opposed NATO and Warsaw Pacts, have been to stay disarmed? I think it is remarkable that nuclear armament has stayed as low as it has.

-Biscuits