The Clash within a Civilisation

At the end of the last century, there was much talk about a future clash of civilisations, replacing the Cold War confrontation. However, the development of events in the early 21rst century has turned the focus upon the clash within one of the largest civilisations of the World: Islam and the Muslim countries. The outcome of the political violence from the civil wars and Salafist terrorism is deaths and casualties beyond imagination. Why cannot the Moslem countries regulate their religious tensions - Sunni-Shia, Salafist jihadism - through institutional innovation, allowing for peaceful settlement and the rule of law?