An analysis 'The Islamic State’s Vulnerability' by:
Daveed Gartenstein-Ross is a senior fellow at the Foundation for Defense of Democracies and an adjunct assistant professor in Georgetown University's security studies program.
Link:http://warontherocks.com/2014/09/the...lnerability/#_

He ends with:
The Islamic State’s many weaknesses will soon become apparent, if they aren’t already. This doesn’t mean that the group will inevitably collapse; and even if it does, its collapse might just mean that its fighters are driven back into the hands of an old familiar foe, al-Qaeda, or other Syrian and Iraqi non-state actors. The United States should approach this fight strategically, understanding both the Islamic State’s weaknesses and also the broader context of the fight.