Long Cycle Theory

Hegemonic stability theory (HST) is a theory of international relations, rooted in research from the fields of political science, economics, and history. HST indicates that the international system is more likely to remain stable when a single nation-state is the dominant world power, or hegemon. Thus, the fall of an existing hegemon or the state of no hegemon diminishes the stability of the international system. When a hegemon exercises leadership, either through diplomacy, coercion, or persuasion, it is actually deploying its "preponderance of power." This is called hegemony, which refers to a state's ability to "single-handedly dominate the rules and arrangements ...[of] international political and economic relations." HST can help analyze the rise of great powers to the role of world leader or hegemon, which have been ongoing since the 15th century. Also, it can be used to understand and to calculate the future of international politics through the discussion of the symbiotic relation between the declining hegemon and its rising successor.

Research on hegemony can be divided into two schools of thought: the realist school and the systemic school. Each school can be further sub-divided. Two dominant theories have emerged from each school. What Robert Keohane first called the "theory of hegemonic stability," joins A. F. K. Organski's Power Transition Theory as the two dominant approaches to the realist school of thought. Long Cycle Theory, espoused by George Modelski, and World Systems Theory, espoused by Immanuel Wallerstein, have emerged as the two dominant approaches to the systemic school of thought.

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