 Nursing assistants labour precarity and political mobilization for the survival of public action in mental health in Brazil, can they fit together? 
In Brazil, several municipalities are subcontracting to meet their needs for mental health staff. The case of auxiliary nurses in the network of the city of Campinas makes it possible to understand the impact of these transformations on precarious workers. The work and mobilization activity of 16 nursing assistants are described from a one-year ethnography. How to reconcile precariousness, the nursing relationship and the mobilization for the survival of public action in mental health? This question is enlightened by tracing the outlines of a «militant grammar» that emerge in the collective spaces of this network. This analysis paves the way for a deeper understanding of the social relationships of power in mental health network. The article concludes the importance of the perspective of nursing assistants in the political nature of their work for psychiatric reform.