The late nineteenth century in Europe saw less the apparition of state management of migrations than a change of system. The “protection of national labor” through identification techniques and border control came to replace the older regime of ex post facto regulation based on the notions of usefulness and subsidiarity (foreigners could be expelled if destitute and ineligible for local welfare). In reaction to this new institutional xenophobia, social reformers, soon helped by the International Labour Office, pushed for bilateral treaties and international conventions guaranteeing migrants similar rights (for unemployment, old-age pensions, labour protections, and so on) as nationals. These transnational negotiations helped the emergence of the welfare state ; they also put in a new perspective the practice of state sovereignty in an area where the Treaty of Gotha of 1851 is still regularly invoked to manage refugee flows.