Two contributions to assessing ISIS. First this in the NYT 'ISIS’ Harsh Brand of Islam Is Rooted in Austere Saudi Creed' and looks at the theological or ideological aspects.

Link:http://mobile.nytimes.com/2014/09/25...html?referrer=

The second is an email based exchange between SME, with the title 'Around the Halls: What is ISIS' Strategy?' hosted by Brookings:http://www.brookings.edu/blogs/iran-...-isis-strategy

The final comment by Charles Lister is a good read, especially on the reaction of 'moderate' Syrian groups - hardly encouraging.