WASHINGTON — Frustrated at the failure to find Saddam Hussein's suspected stockpiles of chemical and biological weapons, U.S. and allied intelligence agencies have launched a major effort to determine if they were victims of bogus Iraqi defectors who planted disinformation to mislead the West before the war. The goal, according to a senior U.S. intelligence official, "is to see if false information was put out there and got into legitimate channels and we were totally duped on it." He added, "We're reinterviewing all our sources of information on this. This is the entire intelligence community, not just the U.S."