In February 2002, Christina Shelton, a career Defense Intelligence Agency analyst, was combing through old intelligence on Iraq when she stumbled upon a small paragraph in a CIA report from the mid-1990's that stopped her. It recounted a contact between some Iraqis and al Qaeda that she had not seen mentioned in current CIA analysis, according to three defense officials who work with her. She spent the next couple of months digging through 12 years of intelligence reports on Iraq and produced a briefing on alleged contacts Shelton felt had been overlooked or underplayed by the CIA. Her boss, Douglas...