Sustainability may be viewed as a principled form of conduct. Among its effects is a growing emphasis on civil society and local governance through which the members of communities are encouraged to rethink democratic ideas and practices, and reconfigure how to live. Although normative, sustainability cannot properly be conceived as prescriptive; such a characteristic would undermine central elements of it, such as participation and equity. In this sense, requiring both mechanisms for community participation in decisionmaking and planning, and an ethic of engagement based on trust, reciprocity, and an acceptance of the rights of noncitizens and nonhuman nature, sustainability might also be construed as a deliberative form of democratic governance. Perhaps problematically, in the last decade this governmental aspect of sustainability has come to be associated with the procedures of communicative rationality. Supported by research conducted over three years in a local government in Tasmania, Australia, we argue that a deliberative and democratic praxis of sustainability may be effective only if and when underpinned by substantive changes to the exercise of power and leadership, and to the ways in which deliberative decisionmaking and planning are pursued. Communicative rationality alone is unlikely to achieve these ends.