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 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."
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, has emerged as the two dominant approaches to the systemic school of thought.
Charles P. Kindleberger is one of the scholars most closely associated with HST, and is even regarded by some as the father of HST. Kindleberger argued, in his 1973 book The World in Depression: 1929-1939, that the economic chaos between World War I and World War II that led to the Great Depression, can be blamed in part on the lack of a world leader with a dominant economy. The theory is about more than economics though: the central idea behind HST is that the stability of the global system, in terms of politics, international law, and so on, relies on the hegemon to develop and enforce the rules of the system. In addition to Kindleberger, key figures in the development of hegemonic stability theory include Modelski, Robert Gilpin, Robert Keohane, Stephen Krasner, and others.