AbstractImplementing sustainable development requires a look at the domestic apparatus of policy making and, in particular, how state and societal actors, such as NGOs, interact in the formulation and implementation of policy. This article adopts a network approach and examines how network structures may condition the degree of cooperative or competitive negotiation processes. Based on theoretical notions in small group and coalition theories, the article suggests that a problem solving orientation will likely unfold in policy communities and that hawkish, competitive behavior will likely manifest itself in issue networks. This relationship produces a dilemma in that issue network structures are more inclined to generate the needed information, exchange, and creativity for addressing the complex agenda items of sustainable development, but actor diversification and transparency in such networks are likely to be barriers to efficient and successful decision-making. After tracing the development and evolution of Swiss climate and biodiversity policies as empirical case illustrations, analysis indicates that the networks identified generally functioned inefficiently, thus supporting the conceptual propositions. Overcoming decision-making obstacles will require effective leadership and process management, clear mandates and network participants which endorse overall objectives, and the development of consensual group history.