How did the nation-state model, once it had emerged in France and elsewhere in the West, proliferate across the globe? Why did the world order of dynastic states, tribal confederacies, and multiethnic empires change into a world made up of states each ruled in the name of its nation? This chapter shows that in contrast to the first nation-states, their subsequent rise across the world was rarely the result of previous nation building. Rather, whether or not a nation-state emerged depended on the configuration of power between adherents of different political projects. Nation-states were established wherever nationalists – who had adopted the model of the first nation-states as their template of political legitimacy – gained the upper hand over representatives of the pre-national regime. More specifically, the balance of power tilts in favor of nationalists the longer they had been mobilizing the population and decrying the ethnic hierarchy of the ancient regime as an instance of “alien rule”; when the imperial center commanded little global economic and military power or was weakened by wars; and when nation-states had been created in the neighborhood or within the same imperial domain, thus offering models of successful nation-state creation and new alliance partners that further tilted the balance of power in favor of nationalists. This chapter thus highlights the exogenous diffusion of the nation-state form, which is adopted wherever the power configuration allowed overthrowing or absorbing exponents of the pre-national order.