The formation of political divergence between the two important military-administrative cities of Iraq, Kufa and Basra, during the caliphate of Uthman ibn Affan (23-35 AH / 644-656 CE) is one of the most influential issues in the events of early Islam. These two regions, initially established with common objectives under the caliphate of Umar, exhibited contrasting reactions on the eve of the crisis in 35 AH; to the extent that Kufa became the main center of opposition, while Basra largely adopted a supportive or passive stance. In analyzing the roots of this distinction, what factors caused this political divergence and turmoil to result in an anti-Uthman uprising in Kufa, but a supportive or passive tendency in Basra? Examination of the data indicates that three key factors were decisive in the political divergence of the two cities: differences in demographic and tribal composition (Kufa vs. Basra), their distinct function and status in the conquests, and the distinct policies of Uthman's caliphate. Considering these points, it appears that the assassination of Uthman cannot be analyzed solely based on religious motives or the appointment of Umayyads. This event occurred within the context of a fundamental divergence between the two power centers of Iraq, which was the product of the interplay of identity factors (the presence or absence of Qadisiya veterans), social factors (tribal composition), and political factors (Uthman's policies regarding conquests and the appointment of governors).