The Rule of Law in an Agnostic World : The Prohibition on the Use of Force and Humanitarian Exceptions

Over the last ten years, we have developed an interactional understanding of international law that connects insights from IR constructivism to the legal theory of Lon Fuller. Drawing on these two influences, our framework posits that legal norms arise when social norms built upon shared understandings meet certain criteria of legality and are upheld by robust practices of legality. In this article, we argue that the interactional understanding of international law, especially in its emphasis on the “practice of legality,” supports a contemporary understanding of the Rule of Law in international society. Our framework highlights that the Rule of Law is not only about constraining power in hierarchical settings, but also about managing and shaping power within “horizontal” systems like international law. We engage with Martti Koskenniemi’s influential accounts of the “culture of formalism” and of the “politics” of international law. Like Koskenniemi’s “culture of formalism,” our account of legality does not presuppose commitments to strong substantive ends or goods. But we suggest that, because all actors are constrained by the requirements of legality and prevailing practices of legality, such a “culture of legality” provides for a relative autonomy of law from politics. We use a case study on recent attempts to create “humanitarian” exceptions to the prohibition on the use of force to illustrate these points, and to show how an emphasis on practices of legality reveals that building and maintaining the Rule of Law is a collective enterprise. Empowered agents (actors in international society) are therefore central, yet international law is not simply what states and other actors want it to be