I’m not sure you said what you think you said, but so be it. The question is whether Saddam was “guilty” of posing the specific threat(s) invoked by the Bush Administration in arguing for, and more or less securing from the U.S. people, consent (or lack of sufficient opposition) to an exclusively pre-emptive war.
The arguments actually relied upon were not about generic threats, and not even about generic “threats to international peace and security.” If you believe the American people would have gone to war over this, and nothing more, persuade me of your hypothetical – but it is a hypothetical, because generic “threats to international peace and security” were not all GWB relied upon, and were presumably believed by his Admin. to be insufficient to convince the rest of the world (as indeed they were, factually, given that he could not persuade the very UN that voted on the resolution that such generic threats were grounds for war).
Instead, the Admin.'s actual lead argument involved ratcheting the threat up to one that Americans would go to war for – a realistic threat of unconventional weapons attack on the U.S. or Americans. Convince me that the religious and social conservatives who are GWB’s core would have endorsed spilling 'Merican blood principally to vindicate a Resolution of a UN that they largely despise and fear, and I’ll reconsider my statement of what actually sold the war.
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Ah, but which threat is the tricky question – which I acknowledged with my supposition that S.H. was doing something along the continuum from bullying poor Abdul down the block to planning mushroom clouds over Peoria. The devil’s in the details of proving where along the continuum.
To get specific, the mere fact that SH did not use the (suppositious) WMDs in the course of being invaded, deposed, emasculated, strongly suggests that either (a) he didn’t have them, or not in the deliverable form claimed by the Admin., and/or (b) he was too sane to use them – either possibility seriously undercuts the “extreme threat to U.S.” that was bread and butter of the Admin. That is true even if WMDs turned up en masse tomorrow (as they haven’t) – if that happened, it could still be argued that SH was a lot more prudent/less dangerous than alleged (like you with your Romulan cloaking device, which it turns out you use only to amaze your friends with magic tricks, or get girls, or impress the neighborhood bullies).
I’m not going to get too much into your appeal to the authority of the UN findings as “proof” of a (specific level of) threat sufficient to justify war, given the aforementioned little problem of the same authority denying that that was their original intent in so resolving, or their preferred response to the threat.
Either the UN’s irrelevant and its desires can be ignored across the board (possibly not a bad idea), or its views of the “threat” have to be reconciled with its opposition to the war as a response to that threat.