After a period of general fervour for social capital, civil society and NGOs’ involvement, current literature is more cautious, trying to test the outcomes of networks’ participation on the quality of democracy. Third Sector political capabilities for voice, negotiation, lobbying and campaigning are very important variables. The article focuses on the formation of these capabilities in a contentious process of policymaking. Starting on a case study in the Lombardy Region, it shows how conditions, mechanisms and processes of Third Sector engagements play a role in the learning and gradual change of political capabilities. Particularly, it stresses the relevance of deliberative arenas for third sector coordination and reflexivity. Looking at the political outcomes in the implementation of the Social Care Reform at the Regional level, the article formulates a hypothesis about the policy dependency of Third Sector legitimate power.