Over the last few decades the number of cases of multiple nationalities worldwide has increased rapidly, and for various reasons this is being tolerated by more and more sovereign states. This is astonishing when one considers that a few decades ago citizenship and political loyalty to a state and, in particular, a specific national political community, were still considered inseparable. Despite the fundamental challenges raised by dual citizenship, the empirical evidence suggests that most immigration states have successfully adapted to problems of sovereignty and legitimacy. State authorities in many immigration countries in Europe and North America have gradually come to see dual citizenship neither as evil nor as an intrinsic value desirable as such. Nonetheless, the degree to which dual nationality is tolerated by states differs widely. Since immigrants themselves have developed manifold strategies to use dual nationality ? states and citizens have been engaged in processes of mutual accommodation. The questions deal with are: What are the factors encouraging the increasing tolerance towards multiple nationalities? How can cross-national differences regarding de jure and de facto tolerance towards dual nationality be explained? And what are the consequences of the growing tolerance towards dual nationality for statehood and immigrant policies? Based on the findings of postnational, national and transnational perspectives the analysis proposes to analyze tolerance and resistance towards dual nationality as a path-dependent process.