He told The Washington Times in an interview that the Islamic State probably figures correctly that the U.S. already "has been droning and bombing" them but will not send in ground troops no matter what.
It's "a very provocative way of showing that you are still a force to be reckoned with" and not just "a bunch of losers," he said. "In this part of the world, honor is power. It's not about doing the right thing. [Honor] is as important to them as martyrdom."