In his book State of War: The Secret History of the CIA and the Bush Administration, James Risen revealed the importance of “the NSA [National Security Agency] story…[where a classified presidential order was signed by Bush on September 17, 2001] authorizing the NSA not only to eavesdrop on Americans without seeking court orders, but to listen in a new way, by intercepting a large volume of communications among categories of people, and then analyzing or ‘mining’ that data in those calls for suspicious patterns that might offer ‘potential evidence of terrorist activity.’ ‘This is the biggest secret I know about,’ one official told Risen.’ The eavesdropping effort is technically known as a ‘special access program’ (SAP), which means that its existence and the information it collects are both tightly held. Within the government, Risen tells us, witting officials referred to it simply as ‘the program,’ and even the legal opinions justifying it are classified.”
– Thomas Powers, The Military Error, Pages 87-88