Realism explains international relations in terms of power.
Realists and idealists differ in their assumptions about human nature, international order, and the potential for peace.
Power can be conceptualized as influence or as capabilities that can create influence.
The most important single indicator of a state's power is its GDP.
Short-term power capabilities depend on long-term resources, both tangible and intangible.
Realists consider military force the most important power capability.
International anarchy—the absence of world government—means that each state is a sovereign and autonomous actor pursuing its own national interests.
The international system traditionally places great emphasis on the sovereignty of states, their right to control affairs in their own territory, and their responsibility to respect internationally recognized borders.
Seven great powers account for half of the world's GDP as well as the great majority of military forces and other power capabilities.
Power transition theory says that wars often result from shifts in relative power distribution in the international system.
Hegemony—the predominance of one state in the international system—can help provide stability and peace in international relations, but with some drawbacks.
Great powers have restructured world order through recurrent wars, alliances, and the reign of hegemons (states that temporarily gain a preponderance of power in the international system). The most important wars have been the Thirty Years War, the Napoleonic Wars, World War I, and World War II. Periods of hegemony include Britain in the nineteenth century and the United States after World War II.
States form alliances to increase their effective power relative to another state or alliance.
Alliances can shift rapidly, with major effects on power relations.
The world's main alliances, including NATO and the U.S.-Japanese alliance, face uncertain roles in a changing world order.
States adopt different strategies for managing state affairs and maneuvering themselves in a world of power politics.
Rational-actor approaches treat states as though they were individuals acting to maximize their own interests. These simplifications are debatable but allow realists to develop concise, general models and explanations.
Game theory draws insights from simplified models of bargaining situations.
