Given that the society as a whole needs a level of production and trade which presupposes urban centres, and given that urban centres (clusters of specialists) are quite incapable of social cohesion and hence of political and military effectiveness, what is to be done? What is done is that the tribes provide cities with rulers: the state is the gift of the tribe to the city. Economically, the tribe needs the city: politically, the city needs the tribe.

XREF: Connects to the broader tension between urban specialization and social cohesion — a recurring theme in political sociology and state-formation theory.

Diego Gambetta, Trust - Making and Breaking…, loc. 1981