U.S. intelligence agencies remain uncertain about danger posed by ISIS

“The American public has come to equate ad­vances in the Middle East by this one group, ISIS, with the danger of another 9/11,” said Paul Pillar, a former deputy director of the CIA’s Counter­terrorism Center.

Pillar said that the Islamic State is following a playbook that is in many ways the opposite of al-Qaeda’s and that making the group the target of a U.S.-led campaign risks turning its focus toward the United States.

“For them to seize and maintain territory is a major digression from terrorist operations in the West, rather than a facilitation of such operations,” Pillar said.

U.S. strikes can certainly degrade the organization, but “there will be a revenge factor,” he said. “The killing of the two captive journalists was depicted by the group explicitly as retaliation for strikes that had already occurred.”