There are three main theories of international relations – Realism, Liberalism, and Constructivism. This video introduces the broad contours and main points of these theories; other lectures in this class will dive into more detail.
First, realism. Realist theorists are primarily concerned with why great powers go to war. This theory has several key assumptions, including anarchy, power maximization, and self help. The assumption that the international system is anarchic means that it has no central organizing authority. A state cannot go to a multilateral institution like the United Nations to guarantee its security – states can only rely on themselves to do that and must help themselves in a world where no other country will. Realism operates at the system level – it focuses on the interaction between states and treats all states as having the same core interests. That national interest is maximizing their power (or, according to defensive realists, their security).
Realists then draw several conclusions about international relations based on these assumptions. Most notably, the international system is characterized by balance of power. This means that if one country rises in power, other countries will respond by increasing their own power. Realism doesn’t rule out cooperation between states, but argues that this cooperation will only be temporary – it will only last as long as it is in a state’s national interest.
The second main theory of international relations is liberalism. Liberalism is a much broader theory than realism, and has three main varieties: Liberal institutionalism, economic liberalism, and foreign policy formulation. Combined, all three varieties assume that states are not all the same – security maximization is not the sole goal of all actors in the international system. Liberal institutionalists and economic liberals, like realists, study relationships between states, but they argue that international institutions and the interdependence created by trade relations shape national interests. Scholars of foreign policy focus on the role that domestic politics – whether that means political institutions, interest groups, public opinion, or individual leaders – plays in determining what a state does in the international system. Based on this assumption that other factors can influence state behavior, liberal theorists also all conclude that cooperation between states is more likely, and longer lasting than realists argue.
The last theory I want to mention is one we are not covering in class. Constructivism, like realism, is a system-level theory, but it focuses on how ideas are created. National identities and ideas like sovereignty are concepts that were created and are reinforced by the behavior of states. So the reason the state system is anarchic, constructivists argue, is because states believe it is. It is possible to change the nature of the state system by changing our actions toward it. That is why constructivists argue that “anarchy is what states make of it.” More generally constructivism focuses on the importance of ideas (like nationalism) and interaction in shaping international politics.
Finally, just a reminder that the names of these theories are just words. Realism isn’t more or less realistic than other theories; liberalism isn’t politically liberal. In this class, your assessment of these theories should be based on your evaluation of their assumptions and logic, not a political position.