The era of the so-called “rightly-guided Caliphate” is generally understood by Muslim historians to have ended with the assassination of Ali ibn Abi Talib in 661 A.D and the subsequent abdication of al-Hasan ibn Ali in the same year. This secured the way for the ascension of Mu’awiyah ibn Abi Sufyan, once amongst the staunchest enemies of Islam and the Prophet Muhammad, to the position of supreme authority in the Islamic world. Although the stability of this regime wasn’t entirely secured until 691, by which time the Hashemite (Husayn ibn Ali) and Qurayshite (Abdallah ibn al-Zubayr) challenges were resoundingly and brutally defeated, many historians have dated its rise to the reign of Mu’awiyah, although its origins may also be sought even earlier. Essentially the emergence and establishment of a regime based on military force and hereditary rule signified the beginning of the dominance of a political culture of authoritarianism, in which sheer military power became the basis for legitimate authority, as explained by Professor Wilferd Madelung below:
“[After the rise of Mu’awiyah], the Caliphate itself was transformed. Sunni tradition recognized the profound change and attributed to the Prophet the tradition that the successorship to Prophethood (khilafat al-nubuwwa) would last after him for thirty years to be followed by ‘biting kingship’ (mulk ladud). No longer was the principle of sabiqa–early merit and service in the cause of Islam–acknowledged as the criterion for the choice of the successor of the Prophet. Instead, swords and soldiers’ boots, the natural prop of despotism, determined thenceforth the identity of the Viceregent of God on earth. The true implications of ‘Uthman ibn Affan’s adopted title Viceregent of God, of being above rather than subject to Islam–from which he personally had shied away in the end–were now fully realized by Mu’awiyah and his successors. The Caliph became counterpart and successor to the Roman-Byzantine Emperor. He took over the old crown lands conquered by the Muslim armies as his divine right. He ruled Muslims as his subjects, absolute lord over their life and death, himself above the law and the lex talionis (law of retribution), killing at discretion whomever he saw as a potential threat to his power.
In a wider historical perspective, Islam was now taken over by the state. Just as three centuries earlier, Roman-Byzantine despotism had appropriated Christianity, strangled its pacifist religious core, and turned it into a tool of imperial domination and repression, so it now appropriated Islam, strangling its spirit of religious brotherhood and community and using it as an instrument of repressive social control, exploitation, and military terrorization. The Roman Emperor, in pagan times deified in order to exact worship from his subjects, had since Constantine become head of the Christian church, the Vicar of Christ on earth, a Christ transformed from a Savior and brother of man into a grim Pantocrator and Judge. The Umayyad Caliph, rival and successor of the Roman emperor in all but name, became the Viceregent of God on earth, a God who now primarily commanded absolute obedience and unquestioning submission to His arbitrary Decree and Ordainment.
The Arabs had now what most of them had dreaded and vigorously resisted for so long. They had lost their freedom and tribal autonomy and become subjects of a state in the form of traditional kingship introduced through the backdoor of Islam. The first step had, as noted, already been taken when Abu Bakr turned the religious obligation of giving alms into an assessable and enforceable tax. The final step was taken under Mu’awiyah, when the duty to obey the Commander of the Faithful was made enforceable under pain of death, rather than imprisonment and deportation as it had been under earlier Caliphs. They had now, as ‘Ali had warned them, the rule of Caesar and Chosroes. Those still remembering their former brotherhood and their brotherhood and their respect for Muslim life under the Prophet and the early Caliphs might wonder what Umayyad state Islam had in common with the message preached by Muhammad. Seeing the odious little impostor posturing as the Viceregent of God on earth, they could well believe that their Prophet had pronounced the hadith attributed to him: ‘When you see Mu’awiyah on my pulpit, kill him!'” (Wilfred Madelung, The Succession to Muhammad: A Study of the Early Caliphate. Cambridge: Cambridge University Press, 1997, pp. 326-327)