The program began with Central Intelligence Agency leaders in the grip of an alluring idea: They could get tough in terrorist interrogations without risking legal trouble by adopting a set of methods used on Americans during military training. How could that be torture? In a series of high-level meetings in 2002, without a single dissent from cabinet members or lawmakers, the United States for the first time officially embraced the brutal methods of interrogation it had always condemned. This extraordinary consensus was possible, an examination by The New York Times shows, largely because no one involved - not the top two C.I.A. officials who were pushing the program, not the senior aides to President George W. Bush, not the leaders of the Senate and House Intelligence Committees - investigated the gruesome origins of the techniques they were approving with little debate. According to several former top officials involved in the discussions seven years ago, they did not know that the military training program, called SERE, for Survival, Evasion, Resistance and Escape, had been created decades earlier to give American pilots and soldiers a sample of the torture methods used by Communists in the Korean War, methods that had wrung false confessions from Americans. Even George J. Tenet, the C.I.A. director who insisted that the agency had thoroughly researched its proposal and pressed it on other officials, did not examine the history of the most shocking method, the near-drowning technique known as waterboarding.