. >> kerr: early on in the war, it seemed quite clear that they were not going to find major stockpiles of weapons, that we were looking at kind of an empty shelf. >> narrator: david kay had been given the job of finding the weapons. >> kay: from very early on, i said, "things are not panning out the way you thought they existed here." and it was specific cases, whether we were talking about the aluminum tubes or we're talking about the nuclear program in general, or the biological program. >> after eight months of searching iraq for weapons of mass destruction, david kay reached a simple conclusion: there aren't any. >> the political stakes are rising in the overestimation of iraq's weapons. the cost... >> narrator: it was an intelligence failure that reverberated throughout washington. >> ...one of the most damaging intelligence failure in recent us history and says the harm to us credibility will take years to undo. >> kay: i think the intelligence community understood that if the american people and the policy makers really understood the message i was delivering, that there would have to be a major shake-up of the way the american intelligence is done, becaus