Many analysts view collaborative institutions that attempt to forge consensus and build cooperation among conflicting stakeholders as a potential remedy to the pathologies of conventional environmental policy. However, few analyses have demonstrated that collaborative institutions actually increase levels of cooperation, and critics accuse collaborative institutions of all talk and no action. This paper reports the use a quasi-experimental design to compare the levels of consensus and cooperation in coastal watersheds with and without U.S. EPA's National Estuary Programs, one of the most prominent national examples of collaborative institutions in the environmental policy domain. Panel survey data from more than 800 respondents shows that while the level of consensus is higher in NEP estuaries, there is no difference between NEP and non-NEP estuaries in the level of cooperation. © 2004 by the Association for Public Policy Analysis and Management.