Cohen explores the origin of realism and argues that a wide range of schools of American legal thought drew from various aspects of legal realism. He notes that these various strands have converged and have become mutually reinforcing. International relations scholarship has been refracted through legal realism; American international law scholarship has borrowed from constitutional law scholarship already suffused with realism. He concludes that American legal realism has always had counterparts in other parts of the world, and one could question whether the thick lines between realism and positivism look much thinner and more porous in actual practice.