This group came into existence towards the end of the fourth decade of the first century of the Hijrah as the result of a dangerous piece of misrepresentation, and before one and half centuries were over, as the result of hysterical temerity and recklessness, they became the object of pursuance by the caliphs, which ended up with their own, and their sect's, annihilation and extermination, and at the beginning of the `Abbasid rule they had become totally non-existent. It was their relentless and spiritless logic, the severity and harshness of their behaviour, the incompatibility of their ways with real life, and, ultimately, their impetuosity (which even did away taqiyah [dissimulation]  in its true and reasonable sense) which caused their ruin and destruction. The Khawarij sect was not one which could in any real sense survive, but its after-effect has remained; the thinking and beliefs of Khawarij have had an effect on the rest of the sects of Islam. Even today, "Nahrawanis" are to be found in abundance, and, just as in the age and time of 'Ali, these are the most dangerous of Islam's internal enemies. Just as there always have been and always will be Mu'awiyahs and `Amr ibn al-`As's, who will use the existence of the "Nahrawanis" when the time is opportune, even if they are counted as their enemies.
. On this doctrine, see `Allamah S. M. H. Tabataba'i: Shi'ite Islam (transl. S. H. Nasr) pp. 223 - 225. (tr. )