I’ve been writing this entire semester about planning for a post-ISIL Middle East.
This article in Foreign Affairs highlights these divisions and discusses how conflict will linger long after ISIL is defeated. It’s important to note that there are not just disputes between different tribes in Iraq, but even conflicts within groups as well. The Kurds, some of the best anti-ISIL fighters in the region, suffer from severe infighting between the different political groups, the PUK and KDP.
The article points out that things will not be rosy and great in Iraq after ISIL is defeated. It is a constant theme in everything I’ve read this semester on the topic, tribalism and ethnic divisions truly dominate the region and these divisions will remain after ISIL leaves town.
https://www.foreignaffairs.com/articles/iraq/2016-11-03/iraq-after-isis