The social theory of migration has attached a marginal role to the State and the law, focusing on demographic, economic and social factors instead. Much of the literature argues that attempts to regulate or limit migratory flows fail in all major industrialised democracies (Hollifield, Martin, Orrenius 2004; Castles 2004). Others have explicitly criticised this idea: the share of international migrants is still quite low and the ability of migratory movements to escape state control is largely overestimated (Freeman 1994; Teitelbaum 2002; Zolberg 2000). There is a need to bring the state and the law back in the social theory of migration. The paper illustrates how migration law is driven by overlapping legal regimes in constant tension between themselves, following a paradox within the migratory policies of contemporary post-industrial democracies: the desire to limit migration (sovereignty) is at odds with dynamics that increase the degree of porosity of borders (market, rights).