International law has always been contested. In recent years, however, competition between States to influence the trajectory of international law has intensified. Unfortunately, most international lawyers and policy makers still employ an impoverished understanding of the way in which international law is created (i.e., through formal international negotiations or as developed through custom). In this article, I argue that this formalist perspective neglects the foundational role of domestic lawmaking and regulation in the development of international law. Indeed, this paper shows that domestic action has historically been a direct causal antecedent to international legal regimes, and concludes that States must fundamentally reconsider the...