1.This threefold division derives from Martin Wight. The best published account of it is his "Western Values in International Relations," in Diplomatic Investigations,ed. Herbert Butterfield and Martin Wight (London: Allen and Unwin, 1967). The division is further discussed in my "Martin Wight and the Theory of International Relations. The Second Martin Wight Memorial Lecture ," British Journal of International Studies 2, no. 2 (1976).