Migration law may be discussed as an example of a clash between two central contradictory globalization processes: first, the transformation of political membership through new forms of quasi-citizenship and their impact for traditional understandings of identity and belonging in the national polity, and second, the securitization of migration and the attempt by the state to control its borders, considered as its “last bastion of sovereignty.” The outcome of this dispute results in conflicting mechanisms of inclusion and exclusion and in illiberal state practices, contrary to fundamental rights, with profound implications for the rule of law in Europe and elsewhere. South America has usually been neglected in academic debates on migration law. This is regretful for two main reasons: first, the development of new liberal ideas on migration in the region which challenge established assumptions on the regulation of migration in Europe, the United States, and elsewhere, and second, the parallel establishment of a South American citizenship. This article will look at this aspect, in particular the Mercosur Residence Agreement, which establishes a free movement of people regime in South America. Its drawbacks and potential will be outlined before exploring possible future scenarios and their importance for other regions, including the European Union (EU).