Combining al Qaeda's significant fighting capabilities with a stronger focus on the administrative capabilities that might permit it to hold ground, the Islamic State copied the latter from Hezbollah's model. Basically, Islamic State is a combined al Qaeda and Lebanese Hezbollah on steroids, destabilizing the region, dissolving borders/changing the political geography in the mid-east, and hardening political positions that make mid-east peace-building more remote by the day.

General Mattis [Ret.] speaking about the Islamic State of the Levant in an interview with Business Insider