WMDs once again
I thought this comment by Paul Snively, which appeared on the recent thread about lying and WMDs, was well-put, and worth highlighting:
Brief logic lesson:
You cannot prove the negation of an existential quantifier in first-order logic given the open-world assumption. The reason is simple: it only takes one counterexample, probably taken from the portion of the open world not considered in the clause at hand, to refute the proof.
Now, Iraq is big, but it's not an open world. In principle, you could prove that there are no WMDs in Iraq at any given point in time. In practice, however, all you can do is talk in probabilities until everyone's satisfied that the probabilities are sufficiently low as not to matter. The only way this works is with a great deal of effort on the part of the government in question. We know what this looks like, primarily thanks to the voluntary disarmament and documenteation efforts of the South African government. The problem with Iraq in the time leading up to the war was that it looked like exactly the opposite: obfuscation, challenge, and rejection right up until the day of the invasion. With Iraq's history of gassing its own people, invading its neighbors, and daily firings on planes patrolling the no-fly zones from Desert Storm, the prudent thing to do was to believe that Iraq had something to hide. And this is only considering the WMDs, while American policy from the Clinton administration to the Bush administration has held some half a dozen other factors to be critical to supporting the policy of regime change. Unfortunately, precisely because the Bush administration believed (correctly, as the criticism reinforces) that the international community would only be impressed by the WMD argument, that was the argument that they presented to the UN (as compared to the Clinton administration, which didn't approach the UN). So now we have the damned if you do, damned if you don't problem: Bush loses because there aren't stockpiles of WMDs in Iraq, and the fact that he went to the UN at all doesn't count. But if he hadn't gone to the UN, the screams about unilateralism and the "rush to war" that took 11 months would be even louder.