This chapter, a contribution to a book on International Legal Positivism in a Post-Modern World, gauges the potential for mutually enriching interactions between international legal positivism and legal realism. It first describes the encounter between legal positivism and legal realism in the U.S. legal academy and then proceeds to discuss the rise of a new legal realism in international legal theory. In a concluding section, the chapter assesses the compatibilities and tensions between the new international legal realism and the new international legal positivism.
With its forthright embrace of the inescapability of uncertainty in law, the new international legal positivism adopts a sceptical position very similar to legal realism. However, this chapter contends, the new international legal positivism still requires a realist supplement in order to provide a fuller understanding of the way in which legal norms interact with non-legal factors and to help us describe, predict and analyse the behaviour of actors in international affairs. At the same time, new international legal realists can learn from the sceptical attitude towards sources of law that new international legal positivists have developed. The two movements can be symbiotic if brought into closer dialogue. Nonetheless, this chapter concludes with a dose of pessimism about the capacity of any of the currently available theories of international law to fully assimilate the complexities of both postmodern theory and postmodern global society into a comprehensive theory of international law in the postmodern world.