Chapter 3 presents comparative case studies of two structural socioeconomic rights rulings: Argentina’s Causa Mendoza – an environmental ruling – and Colombia’s T-760 – a ruling safeguarding the right to health. In both cases, a collaborative oversight arena was created as a result of the convergence of legally empowered advocacy organizations and court-promoted monitoring mechanisms. The collaborative oversight arenas created spaces in which different participants could exercise accountability for unfulfilled commitments from the government and private agents and, more specifically, for the implementation of different aspects of the rulings. Additionally, the creation of spaces for sustained interaction around offered the chance for the diffusion of policy ideas and a rights-based framework, while giving civil society actors access to the state. The case studies also identify unintended and negative consequences from the rulings, recognizing these as integral parts of impact.