After the death of the Holy Prophet (s.a.w.a.), his Caliphate and Successorship was the right of Imam Ali (a.s.), who made several attempts to prove that Caliphate was his exclusive right and that others were mere pseudo-claimants and usurpers. However, after the martyrdom of the Holy Prophet (s.a.w.a.), he found himself alone and could not gather the people towards the obedience of Caliphate entrusted to him by the Holy Prophet (s.a.w.a.). However, he expressed his annoyance concerning the misappropriation of his right on every possible opportunity. Then, be it in a gathering of people or amongst his close confidants, or even while expressing his protest in front of the Caliphs. At every place, he (a.s.) strongly emphasized the fact that the right to Caliphate was his and others did not have any right upon it. He also accentuated that it was an appointment by Allah delivered unto the people through the Holy Prophet (s.a.w.a.). Hence, he disapproved any other principle or law concerning the appointment of the Caliph of Holy Prophet (s.a.w.a.).
The finest example in support of this aim is his retiring himself to his own house. After the death of Holy Prophet (s.a.w.a.), he retired himself to his house and did not pledge his allegiance as a result of which his home was set ablaze. His wife, the only daughter of the Holy Prophet (s.a.w.a.), was wounded and his unborn child, Janab-e- Mohsin (a.s.) was martyred while still in the womb of his mother. Thus, Ali (a.s.) made his right evident and completed his argument upon those who had turned away from the one appointed by the Holy Prophet (s.a.w.a.) and designated by Allah for His Caliphate. Had he gone to the court on his own before their trial of strength and other similar forms of protest, the argument wouldn’t be complete.
Hence, in no way can it be said that he did not take any steps to establish the truth and obtain his right. However, another question that can be answered here as an explanation, that is, why did he not use force to get his right? There are certain reasons for this:
1) Fear of the Nation (ummah) turning apostates:
Ameerul Momineen (a.s.) feared that if he insisted on the evident order concerning the Caliphate, the new converts to Islam would turn away from it. This was so because the hypocrites had reached to power after the death of Holy Prophet (s.a.w.a.) and their might had increased. The hearts of the Muslims were weakening by the day. Tremendous commotion was created in the fundamentals of religion. After the death of the Holy Prophet (s.a.w.a.), the condition of Muslims closely resembled a goat searching for shelter in a freezing dark night after becoming wet in the rains, only to be surrounded from all sides by hungry wolves ready to tear it apart. Some of the Arab tribes had already turned apostates, while some were treading the path towards it.
2) Fear of dissension among the Muslim Ummah:
One of the reasons why Ameerul Momineen (a.s.) chose not to use his might was the fear of dissension and factionalism amongst the Muslim nation. The prevalent condition of the Muslims at that time was the best moment for the unbelievers and the hypocrites to reveal their old plots. Disputes arose amongst the Ansars (inhabitants of Medina) and the Muhajiroon (inhabitants of Makkah) and each one, for some or the other reason, desired the throne of Caliphate. (Or the moment) when Abu Sufyan requested for assistance and support of Ameerul Momineen (a.s.), but he (a.s.) refused, asking him from when had he (Abu Sufiyan) become a supporter and helper of Islam?
3) For Islam’s survival:
Ameerul Momineen (a.s.) desired the survival of Islam at any cost. Being concerned about Islam at that delicate moment, he found it imprudent to use force to seize the Caliphate. Had he taken up arms and revolted along with his few helpers, it would have led to the destruction of the Islamic System after the death of the Holy Prophet (s.a.w.a.). Mischief and destruction among the people would become rampant and all the sacrifices and devotion made till that time would be rendered futile. Hence, for the existence of Islam and the success of the common Muslims, he decided not to stand-up for his right and never revealed any intention for the same. And this last reason holds superiority over all the other reasons mentioned, due to which neither did Ameerul Momineen (a.s.) put up a show of strength nor did he cast out his sword to obtain that Caliphate, for which he was divinely appointed.