In the current global pursuit of Sustainable Development Goals (SDGs), environmental governance in Brazil stands out, especially for its inclusion of social participation in decision-making bodies. The National Council for the Environment (CONAMA) plays a central role in this scenario. Given this, this study asks: How did government changes between 2011 and 2023 influence social participation in this entity, and in what ways did its institutional design vary according to the ineptitude of the current governments? The selected time frame encompasses three distinct moments in the council's design. For the analysis, qualitative methods of content analysis were employed, examining official documents, decrees, and academic publications, providing an in-depth view of the changes that occurred. The results initially reveal a period of strength and prominence, followed by a phase of significant reduction in representation, and later, a moment of reformulation and restructuring of the institutional design of this council. These transitions reaffirm the essential balance between government and social stakeholders in achieving environmental governance. The study emphasizes the imperative of maintaining participatory structures to ensure the quality of environmental policies in the country and realignment with the development of environmental policies at the global level.