The dramatic increase in the level of global governance through multilateral institutions is leading to changes in the theoretical underpinnings of international law and its role in contemporary world politics. In specific, well-defined areas of international law, states have begun to recognize the authority of international consensus over individual state consent as the foundation of legal obligation. Specifically, states have begun to develop a consensus around the control of "excess state violence," defined as a level of violence exceeding that which international political actors consider to be legitimate for pursuing national interests. This includes crimes against humanity, genocide, and grave breaches of the laws of war. In a major shift from twentieth-century practice, states are increasingly recognizing this body of international law as having universal applicability considered binding on all states regardless of whether they are parties to specific treaties. KEYWORDS: international law, Security Council, international organization, state violence, international consensus.
The prevailing theory of international law views voluntary state consent as the primary if not the sole foundation for international legal obligation. Political realists, liberal internationalists, neoliberal institutionalists, and legal positivists all agree that states are required to adhere only to those international legal commitments that they voluntary adopt through their domestic political systems. Such an approach preserves a state's right to reject any principle or obligation that it does not deem to be in its interest to adopt. At the same time, it also strengthens the international legal order by committing states to adhere to those rules that they themselves have agreed to follow. Thus, a consent-based international legal system facilitates cooperation by enabling states to pursue common goals without sacrificing their sovereignty. As a result, consent-based legal norms have dominated international law for more than a century.
Recent trends, however, suggest that foreign policy officials and legal analysts from many states have begun to question whether this is sufficient for addressing some of the most vexing controversies in international relations. For example, can states legally practice genocide if they are not parties to the 1948 genocide convention? Can they legitimately support the use of terrorism against civilians by refusing to adopt international legal agreements that ban the practice? Can a nation's army circumvent the laws of warfare by declaring that the rules do not apply in a particular situation? Can governments allow the practice of slavery within their societies if they have not signed treaties banning it? Can they legally use chemical, biological, and nuclear weapons if they do not sign the biological and chemical weapons conventions? Increasingly, political leaders from a wide range of states have been answering these queries in the negative, suggesting limits to the doctrine of consent in international law. Indeed, in a major shift from twentieth-century practice, states are increasingly recognizing a limited body of international law as having universal applicability considered binding on all states regardless of whether they are parties to specific agreements or whether they are based on customary practice. This raises fresh questions about the way international institutions seek to address the uneasy balance between sovereignty and coexistence in world politics.
In this article, I seek to explain how universal legal norms can coexist within a consent-based legal order by offering a theory of international law that merges the legal with the political. (1) In the following pages, I argue that qualitative changes in the form of global governance through the proliferation of multilateral institutions are expanding the theoretical underpinnings of international …