It's the idea that fringe/outsider groups become more cooperative if they are allowed to participate in the system. I'm not suggesting we give a voice to groups like ISIS, but we can't ignore the fact the Western governments, especially America, play a very active role in creating, fueling, and sustaining anti-American/Western sentiments, and the ability to fight back against America/West is a big reason many join groups like ISIS (or to fight against other local regimes, forming alliances of convenience and opportunity rather than principle and mutually shared ideology).
Clearly the problem is going to take time and small steps to fix, and fighting has proven to only make things much, much worse. Supporting more Liberal Muslim groups in the Middle East while cutting ties to radically Conservative groups, and slowly winning others to "the dark side," and setting off a ripple effect may be the only real thing that can be done to get rid of groups like ISIS.