While the global increase of expatriate dual citizenship acceptance over the past decades has been widely observed, the temporal and spatial contexts of this trend have remained understudied. Based on a novel data set of expatriate dual citizenship policies worldwide since 1960, we find that dual citizenship toleration has increased in the last half century from one-third to three-quarter of states globally. We argue that these domestic policy changes should be understood in light of normative pressure in a world where restrictions on individual choice in citizenship status are increasingly contested and where liberalisation is reinforced through interdependence and diaspora politics. We apply Cox proportional hazard models to examine dual citizenship liberalisation and find that states are more likely to move to a tolerant policy if neighbouring states have done so and that they tend to do so in conjunction with extending voting rights to citizens residing abroad and receiving remittances from abroad. Contrary to other studies, we do not observe significant variation by regime type.
Maarten Vink et al., The international diffusion of expatriate dual citizenship, Migration Studies, 2019.