The argument of this book is that an international system is established for the same reason that any social or political system is created; actors enter social relations and create social structures in order to advance particular sets of political, economic, or other types of interests. Because the interests of some of the actors may conflict with those of other actors, the particular interests that are most favored by these social arrangements tend to reflect the relative powers of the actors involved. That is, although social systems impose restraints on the behavior of all actors, the behaviors rewarded and punished by the system will coincide, at least initially, with the interests of the most powerful members of the social system. Over time, however, the interests of individual actors and the balance of power among the actors do change as a result of economic, technological, and other developments. As a consequence, those actors who benefit most from a change in the social system and who gain the power to effect such change will seek to alter the system in ways that favor their interests. The resulting changed system will reflect the new distribution of power and the interests of its new dominant members. Thus, a precondition for political change lies in a disjuncture between the existing social system and the redistribution of power toward those actors who would benefit most from a change in the system.

This conception of political change is based on the notion that the purpose or social function of any social system, including the international system, may be defined in terms of the benefits that various members derive from its operation (Harsanyi, 1969, p. 532).