Focusing on the 20-year history of unsuccessful proposals for Supervised Drug Consumption Sites in Melbourne, Australia, this paper highlights the generative effects of apparent ‘failure’ in policy-making and policy mobilization. Rather than framing thwarted proposals as categorical failures, we show how they altered parameters of policy acceptability, invigorated policy and practitioner networks, facilitated the development of allied programs, and, recently, inspired a successful SCS proposal. The paper argues that apparent policy failure and the potential for policy change must be evaluated and conceptualised in terms of variously long historical timeframes. In doing so, the paper contributes to ongoing debate over the conceptual and empirical status of failure in policy mobilities literature.