- Peter Bergen notes that U.S. officials expect ISIS to try to stage attacks, but the terrorist group will face greater obstacles in U.S. than in Europe
- Many more militant fighters have returned to Europe, posing the kind of threat seen in the Paris attacks, Bergen says
Peter Bergen is CNN's national security analyst, a vice president at New America and a professor of practice at Arizona State University. He is the author of the new book "United States of Jihad: Investigating America's Homegrown Terrorists" from which this article is in part adapted.
(CNN)CIA Director John Brennan, appearing on the CBS show "60 Minutes" on Sunday, said of ISIS' plans to stage attacks in the United States: "I'm expecting them to try to put in place the operatives, the material or whatever else that they need to do or to incite people to carry out these attacks, clearly. So I believe that their attempts are inevitable. I don't think their successes necessarily are."