From "Burn Before Reading: Presidents, CIA Directors, and Secret Intelligence" by Admiral Stansfield Turner, former Director of Central Intelligence, writing about a government official's take on the CIA's assembling of intelligence pertaining to a hostile nation's atomic program:
"[He] found that the process "rather chills one's blood." [He] saw a complete "lack of integrity" as the "meager stuff" was written up in a way that covered up their uncertainty and lack of information. The reader, he claimed, "is given the impression, and deliberately, that behind the estimates lies specific knowledge, knowledge so important and delicate that its nature and sources cannot be disclosed or hinted at." But in fact, they had little or nothing to show.
What haunted [him] was that someday a president would have to consider serious actions, including "anticapatory retaliation," as a result of CIA reports and estimates that were based on little or no reliable information. Unless intelligence was improved or at least made more honest, then this president or future presidents might start a preventive war "that may have been utterly needless.""
This passage refers to something that happened in 1947, during Truman's administration, and the Soviet search for atomic weapons. It could just as easily refer to more recent events, when intelligence agencies had no "on the ground" intel from Iraq, and came out with estimates telling of "stockpiles of chemical and biological weapons" and an active and imminent nuclear program, which did lead to a "preventive war" that was needless.