Why ISIS surpasses Hitler & Kymer Rouge

Members of ISIS believe that they are the vanguard fighting a religious war, which Allah has determined will be won by the forces of true Islam.

This is the conclusion of a forthcoming book about ISIS by terrorism experts J.M. Berger and Jessica Stern who write that ISIS, like many "violent apocalyptic groups, tend to see themselves as participating in a cosmic war between good and evil, in which moral rules do not apply."

To read Peter Bergen’s chilling analysis of a brutal, savage campaign against anyone who is not a “true believer,” click on http://www.cnn.com/2015/02/16/opinion/bergen-isis-enemies/index.html