Most interesting for its itemization of what the US does NOT know about ISIS.
I should begin by emphasizing that our knowledge of ISIS is extremely scant. We know close to nothing about ISIS’ social base. We know little about how it made its military gains, and even less about the nature of the coalitions into which it has entered with various groups—from other Islamist rebels in Syria to secular Ba‘athists in Iraq.
Sensationalist accounts of “shari‘a justice” notwithstanding, we do not have much information about how ISIS administers the lives of millions of people who reside in the territories it now controls.
Information about the militants who fight for ISIS is likewise scarce. Most of what we know is gleaned from recruitment videos and propaganda, not the most reliable sources. There is little on the backgrounds and motives of those who choose to join the group, least of all the non-Western recruits who form the bulk of ISIS’ fighting force. In the absence of this information, it is difficult to even say what ISIS is if we are to rely on anything beyond the group’s self-representations.