International Customary Law and Articulation Theories: an Economic Analysis

Abstract

Notable scholars have considered the conditions under which rules of customary law can emerge spontaneously through the voluntary interaction and exchange of states in the international community. In this paper, we model the process of international customary law formation under different regimes. We start by considering a traditional model of customary law where legal rules emerge out of past practice. Once established by practice, legal customs enjoy reciprocal application among the states. Our model reveals the limits of the process of custom formation when choices are sequential and players know their roles at the time of strategy selection. After studying the effect of reciprocity, we examine the effects of "articulation" theories, which allow states to commit publicly to a strategy before their respective roles are unveiled. The welfare analysis of the alternative mechanisms of custom formation reveals the advantages and limits of the various processes of customary law formation.

Keywords: Customary law, Custom Formation, Articulation, Norms

JEL Classification: K10, K33, D70