Smart Tourism: Polycentric Governance for Sustainable Cities STORY INLINE POST Contemporary tourism faces a structural contradiction: as destinations consolidate their appeal, the resources that sustain their value — landscapes, heritage, public spaces, ecosystems — deteriorate as a direct consequence of that success. Overcrowding and conflicts between residents and visitors are not management failures; they are the predictable outcome of treating tourism as a service industry rather than as a territorial process involving the intensive use of shared resources. Elinor Ostrom — 2009 Nobel Laureate in Economics — demonstrated that these resources are not condemned to deterioration: the tragedy lies not in the commons themselves, but in the absence of institutions to govern them. In this context, the concept of the Smart Tourism Destination (STD) offers a more comprehensive framework than conventional planning models. Developed by SEGITTUR and adapted to the Ibero-American context by the Ibero-American Network of Smart Tourism Destinations, the STD model is organized around five interdependent axes: governance, sustainability, innovation, accessibility, and territorial intelligence. No axis functions in isolation: innovation without governance produces exclusion; sustainability without participation produces stagnation. Tourism resources are common-pool resources in the technical sense: access to them is difficult to restrict entirely, and their use is rivalrous, in that congestion degrades quality for all users. A beach, a historic centre, or an ecosystem does not deteriorate because it is shared; it deteriorates when no rules exist to structure that shared use. Ostrom was precise on this point: the tragedy described by Hardin is not a tragedy of the commons but a tragedy of open access — of systems with no rules, no monitoring, and no consequences for opportunistic behavior. That distinction determines whether the problem has an institutional solution or only market-based or state-imposed ones. If the problem is open access, the solution is