This thesis analyzes the historical marginalization of the Altindag gecekondu (squatter) region in Ankara, Turkey from the 1920s to the 1970s in the context of capitalist urbanization. The analysis is developed through a critical exploration of the social history of the police that becomes pivotal for the materialization of state power on the urban margins. Deploying a dialectical analysis of the historical matrix of the police, class, and urban space, the thesis reveals the contradictory character of police power shaped by various forms of social, spatial, and political contestations. A tripartite, historically constituted, analytical framework is offered for a radical critique of police power comprised of distinct forms of struggle that reflect the fundamental concerns and foundational contradictions haunting modern police science in the management of capitalist modernity: (1) struggles over urban space; (2) struggles over forms of subsistence; and (3) struggles over a moral order. The thesis explores how these three forms of struggle historically condition the making of social criminality as a practice of subsistence and the production of popular illegality which manifests as an inarticulate and subversive form of moral order on the urban margin. The thesis further explores the cathartic association of social marginality with radical politics in the context of the gecekondu struggles in the 1970s. This reading of police power exposes a relational perspective that acknowledges the historical agency of subordinate classes in the formation and contestation of capitalist modernity. Finally, it is argued that a dialectical critique of police power provides a significant political and theoretical medium through which a radical critique of capitalist modernity from below can be formulated.