The International Diffusion of Expatriate Dual Citizenship Policies

While the global increase of dual citizenship toleration for expatriates over the past decades is a well-known phenomenon, explanations for variation in policies between states still predominantly focus on domestic factors. In this paper we argue that dual citizenship acceptance should be understood in its temporal and international context and viewed as a phenomenon that cannot be solely studied by taking into account domestic attributes of states in specific years. Increasing expatriate dual citizenship toleration is a self-sustaining phenomenon as tolerant policies in states put pressures on those policies in neighbouring states and reverting back to restrictive policies is politically difficult. Based on a novel dataset of expatriate dual citizenship policies since 1960 we show that dual citizenship toleration increases over time, clusters spatially and cannot be adequately explained by hypothesized domestic co-variates. The international diffusion of expatriate dual citizenship implies that dual citizenship intolerance in Europe, as well as in Africa and Asia, will become more isolated as states around the world are increasingly less likely to withdraw the citizenship of expatriates who voluntarily acquire another citizenship.