More important, NOT ONE of the major alliance members---not even France or Germany---said he DIDN'T have them! And it was totally in their interest to say he didn't. No, everyone said up front or tacitly that he had them.
I suppose that shows you the limits of the tacit agreements, then. But I thought part of the shenanigans in the UN security council was about the veracity of the WMD threat. Wasn't Powell criticized because his assessment was a rip-off from a 1990 British term paper, and also because some of the pictures of mobile labs he showed were more than ten years old ? I'll have to look it up.