Theories in the sciences must be subject to constraints, barring the existence of some unified theory of everything. Without boundary conditions, a theory can never hope to fully explain a phenomena or make a prediction. In other words, the constraints a theory takes inform the analysis and the approach to issues it concerns itself with. Additionally, they are not ideologies to be espoused, but a means of understanding or explaining what we observe in the real world. In the following paragraphs I explain why I think that constraints are the key differentiating feature when comparing and contrasting theories in international relations (IR).
Liberalism, first and foremost, according to Moravscik, acknowledges the “primacy of societal actors.” More specifically, the primacy of the individual. Taking the individual as its fundamental unit of analysis, liberal IR theory then builds up to the domestic level; each state in the international arena is up for grabs, that is, domestic political institutions present either “conflictual” or “harmonious” demands until one social group captures the state via political institutions or organizations. Only then can a state, to varying degrees, express its preferences through strategies, trade, and conflict. However, these preferences are separate from the preferences of other international actors, meaning that once domestic politics have been taken into account for one state, they can only manifest in the international arena as strategies or what we might call international affairs. At the international level, Moravscik identifies interdependence as the constraining factor on states. This interdependence derives from the shifting of state preferences. I argue that liberal IR theories vary most obviously and importantly from realism and constructivism when the topic of “constraints” are brought up and that liberalisms constraint, interdependence, is the most flexible.
Realist IR theories posit that the state is the primary actor, and that the international arena is inherently anarchical. It is short-sighted of proponents of realism, on one hand, to discount the citizens that comprise the very thing they wish to study. On the other, it is counterproductive to claim theoretical boundaries and constraints on the very thing they wish to study while claiming that the realm of its existence is anarchy. The theory of atomic physics goes far beyond atoms bumping into one another – it must consider the subatomic particles that govern their interactions for fields such as chemistry to flourish. The constraint, realists claim, is that of one state’s power relative to another. Narrowing a theory to state power effectively leaps over the entirety of Liberalism’s core assumptions while Liberalism builds up to that level but from the viewpoint that the state is divisible. In other words, Realism’s constraint is misinformed, it carries too much generalization while also acquiring a rigidity that is incompatible with a supposedly anarchical world.
Constructivists, as per Onuf, take rules as their constraint, it holds that “people make society and society makes people.” There are various rules that apply to the international arena and an agent has before them an array of choices to make in response to those rules. Constructivism constrains people by limiting what they can accomplish as an individual agent. If people make progress toward their goals through social constructs, then is the unit of analysis in constructivist theories not also the individual? In constraining agents with rules, constructivism actually drowns out the individual as the ever-growing branches of a decision made in response to a rule become an infinite tree. I believe that both liberalism and constructivism yearn to embrace the full complexity of human nature, but liberalism is more flexible as it recognizes the individual as necessarily having to be left out of the consideration of interdependence.
Theories of IR vary most noticeably and can be most clearly differentiated when considering what each takes to be its constraint. Barring the existence of some unified theory of everything, all theories necessarily have boundaries and attempt to predict the nature of things from very unique standpoints. However, liberalisms offer the most freedom within their constraint – interdependence. I argue that this is true because it recognizes the individual as the primary actor while simultaneously recognizing that state preferences give rise to interdependence as opposed to, in the case of realism, anarchy. Constructivism runs the risk of being almost too loose with its recognition of human nature as subject to constraint by rules. Liberalism and constructivism both seek to know something deeper and amass more information than realism does. These key differences arise only when observing the boundary conditions of each theory.