The third and fourth dimensions of wilayat are unique Shi’i beliefs, and they are considered as part of the “dharuriyyat al-madhhab, the essential parts of Shia sect.” It is the common view of our scholars that anyone who rejects one of the dharuriyyat al-madhhab, is not considered a member of the Shia Islam.
It is important to note that whenever the Shias use the term “Imamate” or “Imam”, it encompasses all the four dimensions of wilayat. It excludes neither the spiritual and universal authority nor the social and political leadership. In this sense, the Shi’i term “Imamate” or “Imam” is more comprehensive than the Sunni term “khilafat” or “khalifa”.
In books dealing with the Shia-Sunni debate of the leadership after the Prophet, the focus is more on the socio-political leadership but not in the sense of denying the spiritual and universal authority of the Imam. So while reading or discussing the issue of succession of Prophet Muhammad (PBUH), one should not lose the universal import of the status of an Imam from the Shia point of view.