The primary reason the Bush administration gave for the preemptive invasion of Iraq was the contention that Saddam Hussein possessed weapons of mass destruction and that he constituted a clear and imminent threat to the United States and to the rest of the world. This is what we, the American public and the rest of the world, were told by the Bush administration, based, they said, on intelligence reports they had received. A secondary reason (insufficient to justify a preemptive attack, but presented as a sort of "moral imperative") was to bring democracy to the oppressed Iraqi people.
There are three possibilities:—
It is inarguable that Saddam Hussein had chemical/biological weapons. We know this for two reasons: a) he used poison gas during the Iran-Iraq war and he used it again on the Kurds; and b) we have the receipts, because he got these CB weapons from US back when he was our Son of a Bitch.
1. Saddam Hussein either hid them so well that we can't find them; or he sold them or passed them on to someone else (unsettling thought); or they passed their sell-by date and he disposed of them (quite likely, because the shelf-life of chemical/biological weapons is limited). Finding missiles with empty warheads that were designed for CB weapons would seem to indicate this. It is obvious that he did not have a nuclear program that could have constituted a threat to the United States or anyone else for years to come.
2. American intelligence reports were flawed. There are two possibilities here: intelligence agencies were either mistaken, or they lied to the Bush administration. This does not bode well for any future actions such as preemptive attacks on other nations based on intelligence reports, because it would appear that the intelligence agencies are, for whichever reason, simply not reliable.
3. The Bush administration lied to the American people and to the rest of the world. Why? Control of the Middle East is considered essential to maintaining America's status as sole Superpower in the world. Geopolitical domination of the world is greatly enhanced for whichever country controls the world's major oil reserves—whoever has its hand on the tap. The war on Iraq has been on the Right Wing agenda since the (to them) inconclusive and disappointing end of the Gulf War.