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 states 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 affairs can be seen as a series of bargaining interactions in which states use power capabilities as leverage to influence the outcomes.
Bargaining outcomes depend not only on raw power but also on strategies and luck.
Reciprocity can be an effective strategy for reaching cooperation in ongoing relationships but carries a danger of turning into runaway hostility or arms races.
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 and general models and explanations.
Game theory draws insights from simplified models of bargaining situations.
International anarchythe absence of world governmentmeans 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 worlds 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.
Hegemonythe predominance of one state in the international systemcan help provide stability and peace in international relations, but with some drawbacks.
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 worlds main alliances, including NATO and the U.S.-Japanese alliance, face uncertain roles in a changing world order.