Between Power and Principle: An Integrated Theory of International Law

Over 50,000 international treaties are in force today, covering nearly every aspect of international affairs and nearly every facet of state authority. And yet many observers continue to argue that international law-with its general absence of central enforcement and its typically voluntary character-is ineffective. This Article assesses and responds to this challenge. Building upon insights from both political science and legal scholarship, it offers a theory of state decisions regarding treaty law that accounts for the key ways in which such law shapes state behavior. This integrated theory of international law seeks to explain why countries would commit to treaties that potentially constrain their behavior and how treaties, once accepted, influence or fail to influence state behavior. I argue that commitment and compliance are reciprocal influences on each other. If compliance is very costly or carries few benefits, for instance, countries will be unlikely to join a treaty in the first place. As a result, states behave in ways that standard theories miss-failing to join treaties, for example, with which they could easily comply, or joining treaties that they have little inclination to obey. The theory emphasizes two central means by which treaties shape what countries do. The first is the enforcement of international treaties by transnational actors and by rule of law institutions within nations that join the treaty. In particular, domestic enforcement mechanisms are a crucial force pushing countries to comply with international treaties-and because they are, they are also a key influence upon countries' willingness to join such treaties in the first place. The second is the collateral consequences of treaty membership-that is, the anticipated consequences for, among other things, foreign aid and investment, trade, and domestic political support. Collateral consequences arise when domestic and transnational actors premise their actions toward a state on the state's decision to accept or reject international legal rules. As I demonstrate using both new empirical evidence and reanalysis of earlier studies, the relationship between treaties and state behavior hinges significantly on these two factors. The Article thus offers a vision of the potential and the limits of international law that integrates and moves beyond existing accounts.