PREFACE: This post is by the author of retired blog, Between Worlds. He responds to the "legal analysis" in the Operation Iraqi Freedom FAQ with his thoughts on the legal basis for OIF, including discussion on the limitations of international law enforcement and insight from his experience as a defense attorney. Enjoy:
The legal analysis is about the same as my own, although I didn't research primary material. However, I seem to recall that even some mainstream media at the time published analyses that followed a similar line of thought as we have, namely, that Iraq's failure to abide by Resolution 1441, which itself laid down an ultimatum for Iraq's well-documented failure to abide by the resolutions ending hostilities in 1991, was the proximate legal authorization, which can even be seen as revoking the cessation of hostilities as laid out in the 1991 resolutions.
The discrepancy in the political discourse can be chalked up to exactly that: politics. And of course, differences in politics ultimately reflect differences in policy preferences and Weltanschauung--although the prominence of cults of personality, whether against or for a particular person, certainly figures into the discourse as well.
One interesting point you bring up in your blog is the question of burden of proof. My time as a defense attorney has added nuances to my internal discussion. Those who insist that the burden of proof is on the prosecution tend to see international relations as an extension of domestic criminal law, and are uncomfortable with the power of the US to act as law enforcement and judge/jury. I imagine that, from their point of view, those who do the accusing have the burden of proof beyond a reasonable doubt.
Of course, international relations are nothing like domestic institutions: there are no official legislative, executive and judicial institutions with the power to bind individual states.
Legislative: while statutory international law, in the form of treaties, have a certain binding effect (which the US observes in the breach, by refusing to ratify treaties that may obligate the federal government to legislate in fields where it is not empowered to do so), customary international law does not, other than the fact of its observance--it foists expectations on all nations, and individual states keep count as to who is living up to expectations, and who is not. Yet ultimately, the reality of international relations boils down to the willingness of the powerful to be bound by rules set by the weak. The US, despite its many transgressions, has been extraordinarily willingly to defer to such rules, whereas others, such as Russia, China and even France, tend more aggressively to pursue their national interests, narrowly writ.
Executive: how many divisions does the UN Secretary General have? One of the primary responsibilities of the executive is to send men with guns to enforce the law. The UN has peacekeepers, but they are ad hoc groups assembled for each crisis. There is no global policeman, notwithstanding the longstanding characterization of the US as such. The other primary responsibility is to enforce the law by prosecuting criminal actions against transgressors. The UN does not have its own prosecutors. Uniquely, in international law, prosecution takes place in one of a few international courts, such as the ICJ and the ICC, or in national courts of states that self-proclaim universal jurisdiction, such as Belgium.
Judicial: despite the existence of bodies such as the ICJ and the ICC, many states are not signatories, and may properly refuse to accept their jurisdictions--unless there's something in it for them. The US is not a signatory to the ICC due to fears that its soldiers may become subjects of prosecution brought by various entities. (This may not ultimately be due to lack of confidence in the ICC so much as a desire to maintain the jurisdiction of the UCMJ.) A counterexample is when Serbia ultimately accepted jurisdiction of the Yugoslav War Crimes Tribunal when it became clear that Milosevic's days were numbered, and the EU would not extend more carrots without such acceptance.
In short, international law simply doesn't work like domestic criminal law. While international law has become more predictable over the years, the fact remains that a recalcitrant state may make an unpredictable move with little if any objection; see, e.g., Russian actions against Georgia and Ukraine, and the Saudi-Iranian proxy war in Yemen.
Even if international law could be shoehorned into the strictures of domestic criminal law, the analogies proffered by those who opposed the war are mistaken. The 2003 US invasion of Iraq is not a fresh encounter between an officer of the law and a criminal suspect analogous to officer-involved shooting incidents that have come to light in the news (Ferguson, Baltimore, Chicago, etc.). Rather, Iraq was the beneficiary of a suspended sentence handed down by the UN for Iraq's invasion of Kuwait in 1990. Iraq was essentially haled into court via the Iraq War. The cessation of hostilities was a plea-bargain, where Iraq was placed on probation in exchange for cessation of military hostilities and non-occupation of Iraq. In California, at least, probation is often subject to terms and conditions, which in the case of the end of the 1990-91 Gulf War, were that the Iraqi state had to account for and eliminate all its WMDs and subject certain parts of its territory to no-fly zones. A parallel to California drug laws may be in the form of drug classes (account for and eliminate WMDs) and random searches and drug testing (no fly zones). Continued failure by the Iraqi state to adhere to these terms and conditions meant that the Coalition was not obligated to refrain from renewing hostilities and occupying Iraq. In essence, Resolution 1441 was a "court order" that extended probation and clarified the possible consequences of failure to meet the terms and conditions.
One potential infirmity is that probation is supposed to be for a set term of time. I doubt that the original Gulf War resolutions set a time beyond which WMD inspections would no longer be conducted--meaning that the "probation" was indefinite. Nevertheless, Resolution 1441, as I understand it, cures that infirmity by extending the term of probation--which in California, judges have the power to do when a convict has been found in violation of his probation. The burden of proof in violations cases is probable cause, which is even lower than preponderance of the evidence, a civil court formula awarding victory to the producer of "50%+1" of the evidence. Further, all that was necessary for the "prosecution" to show was that Iraq had failed to cooperate with weapons inspectors; it was not necessary for the "prosecution" to prove that Iraq did have WMDs.
Sorry for the long analysis, but you caught me with a little free time on my hands, so there you go. Feel free to use the material, but please don't use my real name if you do want to use the material. And of course, send me a link if you do use the material.
Reference: International Criminal Court information page related to Operation Iraqi Freedom. Note the decision for OIF is outside ICC's jurisdiction.