Why is Ali ibn Abi Talib regarded as an Imam Ali, if Sunni don't believe in imamate?

 The title "Imam" has different meanings and implications in Sunni and Shia Islam, leading to varied views on the role and status of Ali ibn Abi Talib.

1. **Shia Islam:**

   - In Shia Islam, particularly within the Twelver Shia tradition, the term "Imam" is used to refer to the divinely appointed, infallible leaders who succeed Prophet Muhammad in guiding the Muslim community. The Twelve Imams are considered by Shia Muslims to be spiritual and political successors, starting with Ali ibn Abi Talib and continuing through his descendants, with the twelfth Imam being in occultation and expected to return as the Mahdi.

   - Ali, the cousin and son-in-law of Prophet Muhammad, is revered as the first Imam by Shia Muslims. His leadership is seen as a continuation of the divine guidance initiated by Prophet Muhammad.

2. **Sunni Islam:**

   - Sunni Islam generally does not adhere to the concept of Imamate in the same way as Shia Islam. While Sunnis recognize the leadership of Ali during the early Islamic period and consider him as the fourth Caliph after the death of Prophet Muhammad, they do not attribute infallibility to him or to a specific line of leaders after him.

   - The Sunni perspective on leadership is based on the concept of Caliphate, where leaders are chosen through consensus, election, or other means rather than through a divinely appointed line of succession.

While the title "Imam" is more specific in its theological and leadership connotations within Shia Islam, in a broader sense, it can also be used in Sunni Islam to refer to religious leaders, scholars, or individuals who lead prayers. Sunni Islam does not dispute the historical role of Ali ibn Abi Talib as a companion of Prophet Muhammad and the fourth Caliph, but the theological implications and the concept of imamate differ between Sunni and Shia beliefs.

It's essential to recognize the diversity of beliefs within Islam and the theological distinctions that have developed over centuries, leading to the formation of different branches and traditions within the Muslim community.