Hegemonic Stability Theory
The central idea of this theory is that the stability of the international system requires a single dominant state to articulate and enforce the rules of interaction among the most important members of the system. For a state to be a hegemon, it must have three attributes: the capability to enforce the rules of the system, the will to do so, and a commitment to a system which is perceived as mutually beneficial to the major states. A hegemon's capability rests upon the likes of a large, growing economy, dominance in a leading technological or economic sector, and political power backed up by projective military power. An unstable system will result if economic, technological, and other changes erode the international hierarchy and undermine the position of the dominant state. Pretenders to hegemonic control will emerge if the benefits of the system are viewed as unacceptably unfair. (Extract from lecture notes on the theory of hegemonic stability by Vincent Ferraro, Ruth C. Lawson Professor of International Politics at Mount Holyoke College, Massachusetts.)

International Political Economy
A method of analysis concerning the social, political and economic arrangements affecting the global systems of production, exchange and distribution, and the mix of values reflected therein (Strange, S. 1988. States and Markets. Pinter Publishers, London. p18). As an analytical method, political economy is based on the assumption that what occurs in the economy reflects, and affects, social power relations.

International Regime Theory
A perspective that focuses on cooperation among actors in a given area of international relations. An international regime is viewed as a set of implicit and explicit principles, norms, rules, and procedures around which actors' expectations converge in a particular issue-area. An issue-area comprises interactions in such diverse areas as nuclear nonproliferation, telecommunications, human rights, or environmental problems. A basic idea behind international regimes is that they provide for transparent state behaviour and a degree of stability under conditions of anarchy in the international system. International regime analysis has been offering a meeting ground for debate between the various schools of thought in IR theory. See Krasner, S. 1983. International Regimes. Cornell University Press, Ithaca.

Just War Theory
Normative theory referring to conditions under which (1) states rightfully go to war (jus ad bellum) with just cause, as in self-defense in response to aggression, when the decision to go to war is made by legitimate authority in the state, as a last resort after exhausting peaceful remedies, and with some reasonable hope of achieving legitimate objectives; (2) states exercise right conduct in war (jus in bello) when the means employed are proportional to the ends sought, when noncombatants are spared, when weapons or other means that are immoral in themselves are not used (typically those that are indiscriminate or cause needless suffering), and when actions are taken with a right intention to accomplish legitimate military objectives and to minimize collateral death and destruction. Many of these principles of just war are part of the body of international law and thus are legally binding on states and their agents (Viotti, P. and M. Kauppi, (eds.). 1987. International Relations Theory. Macmillan Publishing Company, New York).

Legal Positivism
A legal theory that identifies international law with positive acts of state consent. Herein, states are the only official 'subjects' or 'persons' of international law because they have the capacity to enter into legal relations and to have legal rights and duties. Indeed, they are the only entities with full, original and universal legal personality; the only proper actors bound by international law. As far as non-state entities (such as individuals, corporations, and international organisations) are concerned, their ability to assert legal personality is only derivative of and conditional upon state personality and state consent. This predominant ideology originated in the nineteenth century when legal positivism took the eighteenth century law of nations, a law common to individuals and states, and transformed it into public and private international law, with the former being deemed to apply to states and the latter to individuals. Thus, only states enjoy full international legal personality, which can be defined as the capacity to bring claims arising from the violation of international law, to conclude valid international agreements, and to enjoy priveleges and immunities from national jurisdiction. (Edited text taken from Cutler, C. 2000. 'Globalization, Law and Transnational Corporations: a Deepening of Market Discipline', in Cohn, T., S. McBride and J. Wiseman (eds.). Power in the Global Era. Macmillan Press Ltd.).

Liberalism (Liberal Internationalism)
Liberalism covers a fairly broad perspective ranging from Wilsonian Idealism through to contemporary neo-liberal theories and the democratic peace thesis. Here states are but one actor in world politics, and even states can cooperate together through institutional mechanisms and bargaining that undermine the propensity to base interests simply in military terms. States are interdependent and other actors such as Transnational Corporations, the IMF and the United Nations play a role.

Marxism
A body of thought inspired by Karl Marx. It emphasises the dialectical unfolding of historical stages, the importance of economic and material forces and class analysis. It predicts that contradictions inherent in each historical epoch eventually lead to the rise of a new dominant class. The era of capitalism, according to Marx, is dominated by the bourgeoisie and will give way to a proletarian, or working class, revolution and an era of socialism in which workers own the means of production and move toward a classless, communist society in which the state, historically a tool of the dominant class, will wither away. A number of contemporary theorists have drawn on Marxian insights and categories of analysis - an influence most evident in work on dependency and the world capitalist system (Viotti, P. and M. Kauppi, (eds.). 1987. International Relations Theory. Macmillan Publishing Company, New York).

Modernisation Theory
A theory presuming that all countries had similiar starting points and follow similar paths to 'development' along the lines of contemporary 'first-world' societies.

Neoliberal Institutionalism
Encompasses those theories which argue that international institutions play an important role in coordinating international cooperation. Proponents begin with the same assumptions used by realists, except for the following: where realists assume that states focus on relative gains and the potential for conflict, neoliberal institutionalists assume that states concentrate on absolute gains and the prospects for cooperation. Neoliberal institutionalists believe that the potential for conflict is overstated by realists and suggest that there are countervailing forces, such as repeated interactions, that propel states toward cooperation. They regard cheating as the greatest threat to cooperation and anarchy as the lack of organisation to enforce rules against cheating. Institutions are described by neoliberals as 'persistent and connected sets of rules (formal or informal) that prescribe behavioral roles, constrain activity, and shape expectations' (Keohane, R. 'International Institutions: Two Approaches', in International Studies Quarterly 32, 1988). Robert Keohane is the scholar most closely identified with neoliberal institutionalism.

Neorealism
Essentially, a systemic, balance of power theory developed by Kenneth Waltz in which states do not seek to maximise power, but merely balance it. And because the international system is regarded as anarchic and based on self-help, the most powerful units set the scene of action for others as well as themselves. These major powers are referred to as poles; hence the international system (or a regional subsystem), at a particular point in time, may be characterised as unipolar, bipolar or multipolar.

Normative Theory
Normative theory deals precisely with values and value preferences. Unlike empirical theory, however, propositions in normative theory are not subject to empirical test as a means of establishing their truth or falsehood. Normative theory deals not with what is, the domain of empirical theory. Rather, normative theory deals explicitly with what ought to be - the way the world should be ordered and the value choices decision makers should make (Viotti, P. and M. Kauppi, (eds.). 1987. International Relations Theory. Macmillan Publishing Company, New York).

Offensive Realism
Offensive realism is a covering term for several theories of international politics and foreign policy that give analytical primacy to the hostile and unforgiving nature of the international system as the cause of conflict. Like defensive realism, some variants of offensive realism build upon and depart from Waltz's neorealism. Offensive realism holds that anarchy (the absence of a worldwide government or universal sovereign) provides strong incentives for expansion. All states strive to maximize their relative power because only the strongest states can guarantee their survival. They pursue expansionist policies when and where the benefits of doing so outweigh the costs. States face the ever-present threat that other states will use force to harm or conquer them. This compels them to improve their relative power positions through arms build-ups, unilateral diplomacy, mercantile (or even autarkic) foreign economic policies, and opportunistic expansion. Ultimately every state in the international system strives to become a regional hegemon - a state that enjoys a preponderance of military, economic, and potential power in its part of the globe. Offensive realists however, disagree over the historical prevalence of hegemonic regional systems and the likely responses of weaker states to would-be regional hegemons (e.g., balancing, buck-passing, or bandwagoning). In particular, there is a sharp disagreement between proponents of the balance-of-power tradition (John Mearsheimer, Eric Labs, Fareed Zakaria, Kier Lieber, and Christopher Layne) and proponents of the security variant of hegemonic stability theory (Robert Gilpin, William Wohlforth, and Stephen Brooks). (Sources: Jeffrey W. Taliaferro, 'Security-Seeking Under Anarchy: Defensive Realism Reconsidered,' International Security, 25, 3, Winter 2000/2001: 152-86; and John J. Mearsheimer, (2002), Tragedy of Great Power Politics, W.W. Norton, New York).

Peripheral Realism
A foreign policy theory arising from the special perspective of (Latin American) peripheral states and represented by the work of Carlos Escude, for example. This view of international relations regards the international system as having an incipient hierarchical structure based on perceived differences between states: those that give orders, those that obey, and those that rebel. The peripheral approach introduces a different way of understanding the internatonal system: that is, from the unique viewpoint of states that do not impose 'rules of the game' and which suffer high costs when they confront them. Thus, the foreign policies of peripheral states are typically framed and implemented in such a way that the national interest is defined in terms of development, confrontation with great powers is avoided, and autonomy is not understood as freedom of action but rather in terms of the costs of using that freedom.

Pluralism
A tradition in international relations that argued that politics, and hence policy, was the product of a myriad of competing interests, hence depriving the state of any independent status. Pluralism can be seen to derive principally from a liberal tradition, rooted in Locke's 'Second Treatise of Government', and to pose an anti-realist vision of the centrality of the state in world politics. Pluralists make four key assumptions about international relations. Primarily, non-state actors are important entities in world politics. Secondly, the State is not looked upon as a unified actor, rather, competition, coalition building, and compromise between various interest groups including multinational enterprises will eventually culminate into a 'decision' announced in the name of the state. Thirdly, pluralists challenge the realist assumption of the state as a rational actor, and this derives from the second assumption where the clash of competing interests may not always provide for a rational decision making process. Finally, the fourth assumption revolves around the nature of the international agenda, where it is deemed extensive by the pluralists and includes issues of national security as well as economic, social and environmental issues. Hence, pluralists reject the 'high politics' 'low politics' divide characteristic of realism. They also contend with the predominance of a physical conception of power inherent in realism.

Policy-Relevant Theory
Policy-relevant theories may have explicit purposes that stem from the value preferences of the theorist, such as reducing the likelihood of war or curbing the arms race. Acting on such theories, of course, is the domain of the policy maker, a task separate from that of the empirical theorist. Theorists who become policy makers may well make choices informed by what theories say will be the likely outcomes of implementing one or another alternative. Their choices may be informed by empirical theory or understanding of world events, but the decisions they make are still based on value preferences (Viotti, P. and M. Kauppi, (eds.). 1987. International Relations Theory. Macmillan Publishing Company, New York).

Postinternationalism
Unlike many other theories, postinternational theory is organized around the premise that our time is marked by profound and continuous transformations and turbulence. It seeks to account for the dynamics of change and anticipate where they might be leading the world. Its prime focus is on the transformation of three basic parameters: one at the micro level of individuals, another at the micro-macro level where individuals and their collectivities interact, and the third is at the macro level of collectivities and their global structures. The central concept at the micro level involves a skill revolution, whereas at the micro-macro level it involves the pervasiveness of authority crises experienced by all kinds of collectivities; and at the macro level it posits a bifurcation of global structures into the state-centric world of sovereignty-bound actors and the multi-centric world of sovereignty-free actors. This formulation is theoretical in the sense that it anticipates the conditions under which continual turbulence and transformation are likely to sustain world affairs. Examples of transformations at each level include the increasingly manifest readiness of individuals to engage in collective action (micro level), the 'battle of Seattle' (micro-macro level), and the pattern - indeed, institutionalization - whereby the NGO and state-centric worlds converge around common interests (macro level). See James Rosenau's (1990) Turbulence in World Politics and Heidi Hobbs' (ed.) (2000) Pondering Postinternationalism.

Postmodernism
A more extreme branch of Critical Social Theory (see above) that can be identified in terms of its critical stance toward (western) modernity and the unambiguous narratives of reason, truth and progress. Whereas the dominant narrative of modernity upholds reason as the foundation of objective truth and the source of progress, postmodernism emphasises the interplay of a plurality of discursive practices, ways of knowing, social identities and possible worlds.

Power Transition Theory
Created by A.F.K. Organski and originally published in his textbook, World Politics (1958), power transition theory today describes international politics as a hierarchy with (1) a "dominant" state, the one with the largest proportion of power resources (population, productivity, and political capacity meaning coherence and stability); (2) "great powers," a collection of potential rivals to the dominant state and who share in the tasks of maintaining the system and controlling the allocation of power resources; (3) "middle powers" of regional significance similar to the dominant state, but unable to challenge the dominant state or the system structure, and (4) "small powers," the rest. The principle predictive power of the theory is in the likelihood of war and the stability of alliances. War is most likely, of longest duration, and greatest magnitude, when a challenger to the dominant power enters into approximate parity with the dominant state and is dissatisfied with the existing system. Similarly, alliances are most stable when the parties to the alliance are satisfied with the system structure. There are further nuances to the theory: for instance, the sources of power transition vary in their volitility, population change being the least volatile and political capacity (defined as the ability of the government to control resources internal to the country) the most volatile. (Best single text and the source of the above description: Power Transitions: Strategies for the 21st Century, by Ronald L. Tammen et al., published by Seven Bridges Press, 2000.)

Prisoner's Dilemma
Cooperation is usually analysed in game theory by means of a non-zero-sum game called the "Prisoner's Dilemma" (Axelrod, 1984). The two players in the game can choose between two moves, either "cooperate" or "defect". The idea is that each player gains when both cooperate, but if only one of them cooperates, the other one, who defects, will gain more. If both defect, both lose (or gain very little) but not as much as the "cheated" cooperator whose cooperation is not returned. The problem with the prisoner's dilemma is that if both decision-makers were purely rational, they would never cooperate. Indeed, rational decision-making means that you make the decision which is best for you whatever the other actor chooses. Suppose the other one would defect, then it is rational to defect yourself: you won't gain anything, but if you do not defect you will be stuck with a loss. Suppose the other one would cooperate, then you will gain anyway, but you will gain more if you do not cooperate, so here too the rational choice is to defect. The problem is that if both actors are rational, both will decide to defect, and none of them will gain anything. However, if both would "irrationally" decide to cooperate, both would gain.

Rationalism
A theoretical qualification to the pessimism of realism and the idealism of liberal internationalism. Rationalists view states as comprising an international society, not merely an international system. States come to be a part of an international society by accepting that various principles and institutions govern the way in which they conduct their foreign relations. In doing so, it can be argued, states also display a commitment to the idea that it is inappropriate to promote the national interest without any regard for international law and morality.

Realism
A particular view of the world, or paradigm, defined by the following assumptions: the international realm is anarchic and consists of independent political units called states; states are the primary actors and inherently possess some offensive military capability or power which makes them potentially dangerous to each other; states can never be sure about the intentions of other states; the basic motive driving states is survival or the maintenance of sovereignty; states are instrumentally rational and think strategically about how to survive.

Social Constructivism
Social constructivism is about human consciousness and its role in international life. As such, constructivism rests on an irreducibly intersubjective dimension of human action: the capacity and will of people to take a deliberate attitude towards the world and to lend it significance. This capacity gives rise to social facts, or facts that depend on human agreement that they exist and typically require human institutions for their existence (money, property rights, sovereignty, marriage and Valentine's Day, for example). Constructivists contend that not only are identities and interests of actors socially constructed, but also that they must share the stage with a whole host of other ideational factors emanating from people as cultural beings. No general theory of the social construction of reality is available to be borrowed from other fields and international relations constructivists have not as yet managed to formulate a fully fledged theory of their own. As a result, constructivism remains more of a philosophically and theoretically informed perspective on and approach to the empirical study of international relations. (Edited passage from Ruggie, J. 'What Makes the World Hang Together? Neo-utilitarianism and the Social Constructivist Challenge', International Organization 52, 4, Autumn 1998).

Traditionalism
An approach to international relations that emphasises the studying of such disciplines as diplomatic history, international law, and philosophy in an attempt to develop better insights. Traditionalists tend to be skeptical of behavioralist approaches that are confined to strict scientific standards that include formal hypothesis testing and, usually, the use of statistical analysis (Viotti, P. and M. Kauppi, (eds.). 1987. International Relations Theory. Macmillan Publishing Company, New York).

Transnational Historical Materialism
Transnational historical materialism falls within the Marxist tradition. This comtemporary Marxism takes its inspiration from Antonio Gramsci and gives greater significance to the role of culture and ideas, along with focussing on economic aspects of order and change. It is seen as a corrective to the economism of classical Marxism.

Transnationalism
Interactions and coalitions across state boundaries that involve such diverse nongovernmental actors as multinational corporations and banks, church groups, and terrorist networks. In some usages, transnationalism includes both nongovernmental as well as transgovernmental links. The term transnational is used both to label the actor (for example, a transnational actor) or a pattern of behavior (for example, an international organisation that acts transnationally - operates across state borders). Theorists focusing on transnationalism often deemphasise the state as primary and unitary actor (Viotti, P. and M. Kauppi, (eds.). 1987. International Relations Theory. Macmillan Publishing Company, New York).

World Capitalist System
An approach to international relations that emphasises the impact of the world wide spread of capitalism. It focuses on class and economic relations and the division of the world into a dominant centre or core of industrialised countries, a subordinate periphery of less developed countries and a semi-periphery of countries that occupy an intermediate position between core and periphery (Viotti, P. and M. Kauppi, (eds.). 1987. International Relations Theory. Macmillan Publishing Company, New York).

World-Systems Analysis
World-systems analysis is not a theory or mode of theorizing, but a perspective and a critique of other perspectives within social science. Its social origins were located in the geopolitical emergence of the Third World in the late 1960s and the manifest insufficiencies of modernization theory to account for what was happening. The unit of analysis is the world-system rather than a state or society, with particular emphases on the long-term history and totality of the system. The notion of totality (globality, unidisciplinarity and holism) distinguishes world-systems analysis from similar approaches such as global or international political economy which look at the relationships between the two segregated streams of politics and economics. Proponents of world-systems analysis also regard it as an intellectual movement, capable of transforming social science into a vehicle for world-wide social change.