[matt4077]

Islamic state really doesn't have much to do with the conflict, except that there was suddenly a lot of territory in eastern Syria that the Syrian state could no longer defend, i. e. a power vacuum.

Northern Iraq was similarly weak, and there was a lot of frustration against the Iraqi government, plus many unemployed former members of Saddam Hussein's military with some experience.

So they thought "fuck it, lets start our own country. With blackflags and dead hookers". A bit like these sovereign citizens, but with better social media.