Just War Theory
http://www.utm.edu/research/iep/j/justwar.htm
"Possessing just cause is the first and arguably the most important condition of jus ad bellum. Most theorists hold that initiating acts of aggression is unjust and gives a group a just cause to defend itself. But unless 'aggression' is defined, this proscription rather open-ended. For example, just cause resulting from an act of aggression can ostensibly be responses to a physical injury (e.g., a violation of territory), an insult (an aggression against national honor), a trade embargo (an aggression against economic activity), or even to a neighbor's prosperity (a violation of social justice).
"The onus is then on the just war theorist to provide a consistent and sound "account of what is meant by just cause. Whilst not going into the reasons of why the other explanations do not offer a useful condition of just cause, the consensus is that an initiation of physical force is wrong and may justly be resisted. Self-defense against physical aggression, therefore, is putatively the only sufficient reason for just cause. Nonetheless, the principle of self-defense can be extrapolated to anticipate probable acts of aggression, as well as in assisting others against an oppressive government or from another external threat (interventionism). Therefore, it is commonly held that aggressive war is only permissible if its purpose is to retaliate against a wrong already committed (e.g., to pursue and punish an aggressor), or to pre-empt an anticipated attack."
At no time has there been evidence that Iraq has an active plan set in motion to attack America pre-emptively. There is no justification for attacking Iraq. In fact, as sited by the following link, where retired senoir intel analyists spoke, the likelihood of Iraq using its alleged WMD is only considered valid if the Americans actually attack Iraq.
http://www.commondreams.org/views03/0207-04.htm
."...a letter from the CIA to the Senate Intelligence Committee asserted that the probability is low that Iraq would initiate an attack with such weapons or give them to terrorists. UNLESS:
"Should Saddam conclude that a US-led attack could no longer be deterred, he probably would become much less constrained in adopting terrorist actions."
"For now, continued the CIA letter, "Baghdad appears to be drawing a line short of conducting terrorist attacks with conventional or chemical/biological warfare against the United States." With his back against the wall, however, "Saddam might decide that the extreme step of assisting Islamist terrorists in conducting a weapons-of-mass-destruction attack against the United States would be his last chance to exact vengeance by taking a large number of victims with him."
fresco has it right, any presumption of "ethical" behavior that promotes attacking first is based upon subjective logic, dishonestly masked in univerals and is no different than what the imperial japanese navy did at pearl harbor. (and i am well aware of the befuddled mistakes in translation of coded messages to the japanese ambassador and delay of the declaration of war japan made that morning in washington that made such attack appear as a "sneak" attack.)