That statement about the evidence Saddam Hussein was hiding weapons of mass destruction was made by one of the most trusted men in America, CBS News correspondent David Martin reports. Weapons inspector David Kay remembers being impressed.
"It was partly because it came with Powell's reputation as much as the individual facts," Kay recalls.
He assumed the intelligence Powell had unveiled was only the tip of the iceberg.
"We have first-hand descriptions of biological weapons factories on wheels and on rails," Powell said in that speech.
"To have detailed diagrams of what those labs looked like, seemed to me, it meant that you had pretty detailed intelligence from inside the program," Kay says.
But after the invasion, Kay was put in charge of finding the WMD, and he found out where those diagrams came from.
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"It was a single source, a source that the U.S. intelligence had never, at that point, talked to. Didn't know his name," Kay says.
The person was, in fact, a fabricator.
The intelligence about Iraq was not all wrong. On the eve of the invasion, CIA analysts, including Paul Pillar, warned the aftermath could get ugly.
"It would be long. It would be turbulent. It would be filled with conflict and probably violence," Pillar had said.
But former CIA officer and now-CBS consultant John Brennan says the administration passed over that intelligence.
"I don't think there was enough attention paid to those assessments that said after the war, after the invasion, there's going to be difficulty in the streets of Iraq and in Baghdad," Brennan says.
Bad intelligence about WMD started the war, but it can't be blamed for all that has happened since.
"We would still have the same bloodshed, instability and destruction even if we did uncover those treasure troves of purported weapons," Brennan says.
Powell now says his U.N. speech will forever be a blot on his reputation.