THE United States has been narrowly saved from lethal terrorist plots in recent years — or so it has seemed. A would-be suicide bomber was intercepted on his way to the Capitol; a scheme to bomb synagogues and shoot Stinger missiles at military aircraft was developed by men in Newburgh, N.Y.; and a fanciful idea to fly explosive-laden model planes into the Pentagon and the Capitol was hatched in Massachusetts.
But all these dramas were facilitated by the F.B.I., whose undercover agents and informers posed as terrorists offering a dummy missile, fake C-4 explosives, a disarmed suicide vest and rudimentary training. Suspects naïvely played their parts until they were arrested.