From Militant Islam Reaches America. New York: W.W. Norton, 2002, pp. 145-55, 293-94.
President George W. Bush provided a good definition of sleepers and the problem they pose in his 2002 State of the Union address: "Thousands of dangerous killers, schooled in the methods of murder, often supported by outlaw regimes, are now spread throughout the world like ticking time bombs, set to go off without warning." Sleepers—those seemingly law-abiding individuals who live quietly and inconspicuously near the scene of their future operations, waiting for orders to spring into action—make up one of the leading security problems facing the United States. Indeed, one day after that speech, FBI director Robert S. Mueller expressed his fear that "sleeper cells" exist within the United States and declared that they require the country to remain on extended high alert. Please continue.