Charles Mills In his book A History of Muhammadanism, Charles Mills assessed Hadrat Ali as follows: “As the chief of the family of Hashim, and as the cousin and son-in-law of him whom the Arabians respected almost to idolatry it is apparently incredible that Ali was not raised to the caliphate immediately after the death of Muhammad p.b.u.h.
Suala linaluhusiana na ukhalifa (uongozi wa Waislamu baada ya Mtume s.a.w.w) na ambalo lilijadiliwa na kuzungumziwa katika zama za Mtume Muhammad (s.a.w.w) na Maimamu wetu (as) na halikutiliwa shaka baina ya Waislamu ni kuwa, awali mtawala na khalifa anapaswa kuwa mjuzi wa sheria za Kiislamu, yaani mtaalamu wa sheria.