摘要：There is no corpus of law that is global in nature. Rather, “global” migration law is a collection of legal instruments situated at levels ascending from the subnational to the international levels. International law instruments contribute to the global governance of international migration at the international and regional levels. Two issues arise with respect to the effectiveness of these instruments: voluntary state accession and subsequent enforcement, even when states are parties to them. Domestic law regulates issues of international migration at the national and subnational levels. Enforcement is assumed to be more effective here. But this effectiveness varies according to the power of states, their levels of development and their capacities.
