Add to ORKGThis paper presents a model of nations where culturally heterogeneous agents vote on the optimal level of public spending. Larger nations benefit from increasing returns in the provision of public goods, but bear the costs of greater cultural heterogeneity. This tradeoff induces agents' preferences over different geographical configurations, thus determining the likelihood of secession or unification. We provide empirical support for choosing genetic distances as a proxy of cultural heterogeneity and by using data on genetic distances, we examine the stability of the current map of Europe. We then identify the regions prone to secession and the countries that are more likely to merge. Furthermore, we estimate the welfare gains from European...