In this article, the authors present a "telling case" of the history of the Santa Barbara Classroom Discourse Group (SBCDG) and describe how policies supported and constrained the work of this sustaining community. As a telling case, this discussion of policy issues that were constructed and faced by members of the SBCDG does not claim "typicality." Rather, this case is designed to make visible new or grounded understandings of how community development is a nonlinear process and how policy is both constructed by members and externally framed in ways that support and/or constrain what members were able to do together and with students. By tracing the impact of developing and shifting policies from the classroom level to the larger contexts in the ongoing collaborative projects, the authors present a series of lessons about policy issues in five areas: Access, Entry to Classrooms, Data Collection, Publication, and Data Ownership.