The argument of this chapter is that states make cost/benefit calculations in the determination of foreign policy and that a goal of a state's foreign policy is to change the international system in ways that will enhance the state''s own interests. Whether these interests are power and security (as political realists argue), capitalistic profits (as Marxists allege), or welfare gains (as many contemporary theorists contend), every state desires to increase its control over those aspects of the international system that make its basic values and interests more secure.

However, although a group or state may desire to change the international system in order to advance its interests, the effort to do so necessarily involves costs; the group or state not only must have sufficient resources to meet these costs but also must be willing to pay such costs. Therefore, a group or state will attempt to change the system only if the expected benefits exceed the expected costs; that is, there must be an expected net gain. To put it another way, the group or state will seek to change the system only if it is believed that such change will be profitable (Davis and North, 1971, p. 40).