Parity and primacy in perspective : a second Anglophone decline or a second American century?

Much of the systemic theory in international relations focuses on a single explanatory variable: the distribution of capabilities, widely understood to be synonymous with the distribution of power. Despite the significant attention given to the distribution of power, there is still fundamental disagreement about how the distribution impacts the stability (durability and peacefulness) of the international system. Balance of power theory claims that the system is most stable when power is diffused among multiple states; when there is a balance of power. Hegemonic stability theory claims that the system is most stable when power is concentrated within a state or small group of states; when there is a preponderance of power. This paper 1) reviews the literature of balance of power theory and hegemonic stability theory; 2) uses each theory to explore the case of Great Britain in the mid-nineteenth century; and 3) analyzes contemporary American foreign policy through the lens of the two theories. In the third section, this study asks such questions as: How have balance of power theory and hegemonic stability explained contemporary American grand strategy? How has balance of power theory (which has traditionally been applied to bipolar and multipolar systems) been adapted to explain the dynamics of a unipolar world, and are those adaptations (soft balancing and leash-slipping) convincing extensions of the theory? Is the present unipolarity merely an "illusion," or is it both "peaceful and durable?" Given the answers to these questions, how ought the United States to conduct its foreign policy? Should it "pull back" or "lean forward?"