Treaty Penumbras

The classic question in international law concerns its effectiveness. Today, this old debate concerns the usefulness of treaties. Yet those engaging in this debate share a common problem. They evaluate treaty success by focusing on the effects of treaties on one type of actor: states. This narrow lens is misguided; it leads to a skeptical view of the effectiveness of treaties because of the number of countries declining to negotiate, adopt, ratify, or enforce treaties.This article challenges this skeptical view by introducing the concept of “treaty penumbras” to explain how even treaties rejected by state actors exert considerable effects on the actions of an important non-state actor: transnational businesses. This article identifies three types of penumbral effects: pre-emption, coordination, and noise. Pre-emption effects encourage businesses to upgrade their self-regulation when a treaty is imminent. Coordination effects galvanize business actors to support (or oppose) treaty norms, and noise effects increase external pressure for corporate reform. Each of these effects magnifies the reach of treaties over businesses but these effects are unnoticed in the traditional legal framework that prioritizes state behavior.Penumbral effects have important policy and academic implications. National policymakers, individually and collectively, increasingly target corporate transgressions globally, such as human rights abuses, environmental contamination, and financial misconduct. Treaties are designed to address these very problems but are increasingly limited in doing so under the traditional “statist” framework. In contrast, this article offers strategies for operationalizing penumbral effects to reach corporate conduct through treaty regulation. For academics, penumbral effects necessitate reevaluation of both the criteria used for evaluating the effectiveness of treaties and the conclusions reached under that evaluation