Warning: this video is violent and may be too difficult for some viewers to watch
It is hard to overstate ISIS' ambition or its thirst for blood. Recently a VICE News filmmaker spent time with ISIS fighters in Syria. He witnesses the grisly end and aftermath of a battle with a Syrian army unit.
What does it take to defeat a force like ISIS, when they are ready to use such brutal tactics? Anderson discussed possible strategies with retired U.S. Air Force Lt. Col. Rick Francona and David Kilcullen, who advised Condoleezza Rice and Gen. Petraeus on counterinsurgency.
Anderson Cooper goes beyond the headlines to tell stories from many points of view, so you can make up your own mind about the news. Tune in weeknights at 8 and 10 ET on CNN.
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