Is the Bush doctine at risk?

George Will believes that “the failure — so far — to find, or explain the absence of, weapons of mass destruction” places the Bush doctrine of preemptive war in jeopardy. Will argues that “preemption presupposes the ability to know things — to know about threats with a degree of certainty not requisite for decisions less momentous than those for waging war.” Will presents, and seems to find plausible, James Woolsey’s explanation for the current state of affairs. However, he concludes that “until WMD are found, or their absence accounted for, there is urgent explaining to be done.”
I agree with Will up to a point. We do need to figure out what the situation is with respect to WMD and whether (or to what extent) and why our intelligence was faulty. And if it turns out that we were wrong about WMD in Iraq, this should give us pause. However, the decision whether to initiate future preemptive wars should not depend to any great degree on the inquest regarding Iraq. There may be situations in which a dictator announces or admits that his country possesses WMD (actually there is such a situation — North Korea). In that case, the problem of imperfect knowledge will not exist. In other instances, the quality of our intelligence might be incontrovertible (think of the Cuban missile crisis). Or there may be situations in which the government lacks high-quality intelligence but makes a convincing case that the danger of assuming the risk, perhaps coupled with other reasons, justifies going to war.