The study highlights the political issue that played a major role in shaping the system of government in the Islamic state. This is the creation of the system of "heir apparent" by Mu'awiyah bin Abu Sufian, the Umayyad Caliph. The study follows a descriptive approach based on historical analysis and comparison of accounts, and then follows the reactions against that system. The findings of the study show that the system of "heir apparent" was one of the causes of bloody conflicts and violent strife experienced by the Islamic State, and was, in fact, a major cause of the fall of the Umayyad State in the East, in 132 AH / 750 AD.