The aims of this paper are: (a) to analyze continuities and changes in American international relations (IR) theories in the post-war era in terms of their basic propositions, norms, policy prescriptions, and methodologies and (b) to examine the relationship between the changes in the IR theories on the one hand and the developments of international politics and changes in the American position in world politics on the other.<br>The United States' academic community accepted the balance-of-power (BP) theory as its central IR theory in the 1940s and 1950s, not because of its logical consistency and explanatory power but mainly because of its norms (national interests) and policy prescriptions for the United States in the Cold War setting. Since the late 1950s the BP theory has been used as a descriptive and explanatory model of international politics as well as a policy guide for the United States, and it was, along with other IR theories, subjected to rigorous scientific analysis. There existed a belief that humans are able to control international politics and particularly to achieve peace (rather than undefined national interests) through such scientific analysis.<br>However, since the late 1960s, due to the Vietnam trauma, the BP theory has been seriously challenged even though it has never lost its status as a major IR theory in the United States. New theories have been sought in order to explain new developments in international politics, such as international economic instability and ecological constraints. The interdependence theory, which not only takes into account varied kinds of actors in international politics but also is applicable to varied issue areas, has emerged as a fairly comprehensive IR theory. Furthermore, due to a lack of indigenous theories on reasons for international hierarchy, the dependency theory was introduced into the United States in order to analyze relationships between developed and developing countries.<br>Currently, three major IR theories are widely accepted in the United States: the BP theory; interdependence: and dependency (presently this is developed into a more comprehensive world system approach). Each has its own basic propositions, its own specialized fields (politico-military, international economy and the Third World, respectively), and its own norms (national interests/peace, maximization of welfare, and distributional justice, respectively). Each also gives a different identity to the United States in world politics (the major military and political power, the primus inter pares in the international economic system, and the nation which exploits the Third World, respectively).<br>American IR the ories have both “particularity” bound by the American position in world politics, and enough universality so that others can utilize them to analyze international politics.