...

Let's start with the issue of just cause.

The possibility of a war with Iraq has been around since George Bush's 2002 State of the Union Address where he named Iraq as one of the three members of the "axis of evil":

States like these, and their terrorist allies, constitute an axis of evil, arming to threaten the peace of the world. By seeking weapons of mass destruction, these regimes pose a grave and growing danger. They could provide these arms to terrorists, giving them the means to match their hatred. They could attack our allies or attempt to blackmail the United States. In any of these cases, the price of indifference would be catastrophic.

We will work closely with our coalition to deny terrorists and their state sponsors the materials, technology, and expertise to make and deliver weapons of mass destruction. We will develop and deploy effective missile defenses to protect America and our allies from sudden attack. (Applause.) And all nations should know: America will do what is necessary to ensure our nation's security.

...