Realist Assumptions
*Analytic unit: state is the principal actor.
*View of actor: state is unitary actor.
*Behavioral dynamic: in its foreign policy, the state is a rational actor seeking to maximize its own interest or objectives.
While realist recognize that nonstate actors exist, non state actors are not as important because, ultimately, they are responsible to state or are vulnerable to state action.

Anarchy: the absence of a higher authority. The absence of a high authority requires state to engage in self-help in other to guarantee their own security and other national interests. IOs are extentions of great powers.

Liberal assumptions
*Analytic unit: state and nonstate actors are important.
*View of actors: state disaggregated into components; some may operate transnationally.
*Behavioral dynamics: foreign policymaking and trans- national processes involve conflict, bargaining, coalition, and compromise—not necessarily resulting in optimal outcomes.
*Issues: multiple agenda with socioeconomic or welfare issues as, or more, important than national security.

Humans are self interested but are also cooperative economic creatures liberals see IOs in one of two ways, some see IOs as the early Institutions of world government. The IOs are evolving into supranational organizations that excercises authority and jurisdiction over nation state.
*Global governance is based on interations several kind of actors; state, individuals, interest groups, etc competing and working together.

Marxism Assumptions
*Analytic units: classes, states, societies, and nonstate actors operate as part of world capitalist system.
*View of actors: international relations viewed from historical perspective, especially the continuous development of world capitalism. *Behavioral dynamic: focus is on patterns of dominance within and between societies. *Issues: economic factors are most important. constructivism, and its theory of institutions being a socially constructed concept determined by the sharing of ideas; it will finally conclude with the idea that institutions play a crucial role in the international system.
* The idea of anarchy and power politics has been essentially reduced, and according to notable constructivist Alexander Wendt, “if today we find ourselves in a self-help world, this is due to process, not structure. There is no ‘logic’ to anarchy apart from the practices that create and instantiate one structure of identities and interests rather than another; structure has no existence or causal powers apart from process.” constructivism challenges both neo-realism and neo-liberal institutionalism by claiming that anarchy is not inherent in the state system, as affirmed by neo-realists, neither is it inexistent, as affirmed by neo-liberal institutionalists, it is, in truth, what States make of it. It asserts that institutions and structures, within the international system, are mutually constructed concepts by actors that employ social practice to define the ‘international realm.’ The previous theories, neo-realism and neo-liberal institutionalism, take for granted the idea that economic and military power is the primary source of influence in world politics. Constructivist theorists counter this, as they believe discursive power also plays a fundamental role in the understanding of the global political system. Constructivists deviate from the neorealist assumption that anarchy plays a crucial role in the behaviour of institutions, and alternately create a carefully depicted discourse of the role identity and interest in the shaping of international actors.

The neo-realist approach argues that international institutions are and always will be fundamentally ineffective, as they cannot prevent States from being self-interested and engaging in power politics. Scholars such as John Mearsheimer believe that institutions only have marginal power, giving way to an arena of power relations between States, making them a