Though apparently ‘Ali was also included in it...
Though apparently ‘Ali was also included in it, the rulers were such that only the one who was having the same opinions as Umar, had any chance to succeed.” This incident on one hand bestowed caliphate to Uthman and on the other provided the community with yet another principle of caliphal appointment. Now along with consensus and testament, the ‘Shura’ also became a valid method of appointing a caliph.
Since at the end of the third period, the Islamic community has thrown aside from its neck every illegal compulsion and influence and the slain caliph had not been able to make arrangement for the next caliph after him according to his wishes, all the Muslims unanimously submitted to the original caliph selected by the Messenger of Allah (s.a.w).
However, in this long period, moods had changed and a caliphate based on justice and truth was problematic to people inclined towards falsehood, therefore, first of all Talha and Zubair instigated Ayesha to participate in the Battle of Jamal so that this caliphate may be exterminated. After that Muawiyah began to enact bloody dramas on the plains of Siffeen.
Those who considered Amir al-Mu’minin ‘Ali bin Abi Talib (a.s) as the Prophet’s successor according to “divine appointment”, for them everyone who forsook the legitimate caliph deserved the death penalty. But those who considered consensus as the basis of this caliphate, for them these battles were very patience-testing.
After the martyrdom of Amir al-Mu’minin (a.s), Imam Hasan (a.s) reached the position of Imamate according to “divine appointment.” The intrigues of Muawiyah compelled the military officials of Imam Hasan (a.s) to act as his agents and Imam Hasan (a.s) could not have any choice but sign the treaty with Muawiyah and abdicate.
According to the rule of: “whatever happened is appropriate and legal”, Muawiyah who had become eligible for death penalty due to the rule of: “When two persons reach caliphate…”, now was the rightful caliph.