“This last year has been a very hard year for them,” a senior U.S. counter-terrorism official said of Al Qaeda militants, whose operations he tracks in northwest Pakistan. “They’re losing a bunch of their better leaders. But more importantly, at this point they’re wondering who’s next.”

U.S. intelligence officials said they see clear signs that the Predator strikes are sowing distrust within Al Qaeda. “They have started hunting down people who they think are responsible” for security breaches, the senior U.S. counter-terrorism official said, discussing intelligence assessments on condition of anonymity. “People are showing up dead or disappearing.”