This is a lengthy article and perhaps you missed it but that divide is mentioned:
Obviously, the enemies of the Islamic State and its jihadist allies are not only the Crusaders or the West. Some of Islams bloodiest wars were its invasion of Hindu India, where the tension remains marked. There are also Muslim efforts into China. The Philippines has a major problem as does Russia. But Islam wars with itself. The Sunni/Shiite struggles are legendary. It is important to note that one of the first things on the Islamic States agenda, if it is successful in surviving, is to unite all of Islam in its creedal unity.
It further develops the impact of this, regionally ...
All existing Islamic states are some sort of compromise between the true Islamic mission and forces, usually military forces that limit this world-wide unification. Almost all standing Muslim governments recognize the danger to themselves of a successful Caliphate. They all have some form of jihadist presence within their boundaries that seek to control it in the name of their very survival.
Perhaps that is why Bahrain, Jordan, Qatar, Saudi Arabia and the United Arab Emirates are joining forces with the US.
I do not trust any such partnership. They are "joining forces" to save their own hides ... that's it. They will turn on us in due course. Do you really think the Muslims in these countries care about us?
This is what I mean about tactical errors. Why protect Muslims from other Muslims?