Political institutions develop when the complexity of the society reaches the point at which kinship organization can no longer serve as an adequate mechanism for carrying out the political functions of the society. The following may be identified as political functions: (1) to protect the society from external threats (2) to insure order in the society (3) to resolve conflicts within the society, and (4) to allocate resources of the society. In simple, homogeneous societies there seems to be widespread agreement on the values that underlie solutions to these social requirements. But complexity implies a measure of diversity of interests and values. Consensus cannot be taken for granted, for solutions that benefit one set of interests may have detrimental effects on another. Questions arise to challenge the assumption that there is a common interest and that universally satisfying solutions to problems can be devised: Whose interests need protection from external threats? Whose norms provide the basis for order? Whose interests are served in conflict resolution? Who gets what in resource allocation? Order at which price? Because people at different positions in the social order tend to offer different answers to such questions, choices among alternatives are necessary. It is obvious, then, that control of the apparatus through which these decisions are made and implemented is of crucial import. The essence of political process is the struggle between individuals and groups with different interests to gain the decision-making power. Power refers to the ability of an individual or group to have its will carried our even in the face of opposition to it. In terms of political functions it means being in a position to determine the answers to questions issuing from social complexity that concern whose interests and values are to be addressed. Conflict and functional theorists differ in their conceptions of political power. Functionalists assert that only through some concentration of power can collective goals be achieved. They view the state apparatus as a mechanism for accomplishing these positive goals. Conflict theorists, on the other hand, view the state as serving the ruling economic class and see its function as maintaining the dominance of this class. What is the main topic of this passage?