We live in a world of legal pluralism, where a single act or actor is potentially regulated by multiple legal or quasi-legal regimes imposed by state, substate, transnational, supranational, and nonstate communities. Navigating these spheres of complex overlapping legal authority is confusing, and we cannot expect territorial borders to solve all these problems because human activity and legal norms inevitably flow across such borders. At the same time, those hoping to create one universal set of legal rules are also likely to be disappointed by the sheer variety of human communities and...