The purpose of this paper is to analyze the transformations in the frameworks of reflection and action that promoted territorial documentation policies, developed in coordination between the National Direction of Migration and the provincial and municipal governments in the southern area of Greater Buenos Aires, Argentina. Based on an ethnographic approach to the activities of a local office, the Dirección de Entidades y Colectividades de La Plata, and interviews with its main managers, we focus on the interrelation between documentation policies and the visibility (and production) of the electoral potential of foreigners that crystallized during the implementation of these programs. Unlike the literature that focuses on the analysis of the intentions (explicit or implicit) of the laws and projects, and on the difficulties encountered in achieving the purposes stated in them, the originality of the article is given by its monitoring of positions, relationships, languages, and objects that were produced (to some extent unexpectedly) during their implementation. This strategy reveals that the documentary programs and the officials who carry them out have gradually become part of the networks of the so-called territorial policy, in which the relevance assigned to foreigners has increased. The fundamental shift in this dynamic is the progressive recognition of its electoral potential and the conceptualization of the migration issue as an area of strategic dispute for local and provincial political life. Thus, the main conclusion is that throughout the implementation of these programs, migration policy became politicized; that is, it acquired a “political” status in the consideration of different relevant actors. This recognition lasted even after document operations were discontinued in 2016 and was part of their reinstatement in 2019.