In modern societies foreigners are implicated in the resolution of the problem of state sovereignty. This paper clarifies how foreign groups can be used by the state to reconstitute the nation in such a way that vulnerabilities are mended. Michel Foucault's racism and bio-politics are used as conceptual tools to gain insight on how the perpetually open question of who belongs and who does not belong to the population might be settled. This theoretical problem is illustrated with the help of case studies on two significant "crisis moments" for the Swiss state: the arrival of the Hungarian refugees in the late 1950s and the arrival of the Bosnian refugees in the early to mid 1990s.