Previous chapters have looked at the characteristics of individual states and at the two-country problem of cooperation. This part moves beyond dyads to look at the international system, especially the norms characterizing that system. I also introduce the concept of a regime, distinguishing it from both norms and behavior.

As in the rest of this book, I make a point of looking at variables that actually vary. This differs from many other theories' treatment of systemic-level characteristics, including norms. For example, Kenneth Waltz's (1979) Theory of International Politics examines only anarchic systems made up of nation-states, so that two of his three variables (the ordering principle and nature of the unit) do not vary; the third variable in Waltz's theory, the distribution of capabilities, does vary. Though differing from Waltz on almost every other dimension, Martha Finnemore's (1996) National Interests in International Society also does not study variation at the systemic level, but explicitly looks only at countries that share a given norm. Representing yet another tradition, Immanuel Wallerstein (1979, 1989) examines an international system that evolves and is internally differentiated, but his conceptual framework also does not allow central features of a world system, such as capitalism itself, to vary.