On September 17, 2001, President Bush signed a secret Presidential finding authorizing the C.I.A. to create paramilitary teams to hunt, capture, detain, or kill designated terrorists almost anywhere in the world. Yet the C.I.A. had virtually no trained interrogators. A former C.I.A. officer involved in fighting terrorism said that, at first, the agency was crippled by its lack of expertise. “It began right away, in Afghanistan, on the fly,” he recalled. “They invented the program of interrogation with people who had no understanding of Al Qaeda or the Arab world.” The former officer said that the pressure from the White House, in particular from Vice-President Dick Cheney, was intense: “They were pushing us: ‘Get information! Do not let us get hit again!’ ” In the scramble, he said, he searched the C.I.A.’s archives, to see what interrogation techniques had worked in the past. He was particularly impressed with the Phoenix Program, from the Vietnam War. Critics, including military historians, have described it as a program of state-sanctioned torture and murder. A Pentagon-contract study found that, between 1970 and 1971, ninety-seven per cent of the Vietcong targeted by the Phoenix Program were of negligible importance. But, after September 11th, some C.I.A. officials viewed the program as a useful model. A. B. Krongard, who was the executive director of the C.I.A. from 2001 to 2004, said that the agency turned to “everyone we could, including our friends in Arab cultures,” for interrogation advice, among them those in Egypt, Jordan, and Saudi Arabia, all of which the State Department regularly criticizes for human-rights abuses.