Аннотация:This study examines changes from 2000 to 2010 in the adoption of sustainability plans and policies in a sample of U.S. cities. The study’s framework posits sustainability initiatives as communitarian outcomes intended to meet the needs of both current and future generations. We hypothesize, accordingly, that a community’s social capital level, in the form of the relative presence of social trust, is a primary facilitating condition for the adoption of sustainability initiatives. The analysis assesses whether trust-based social capital is similarly associated with the adoption of plans and policies at both time points (2000 and 2010), as well as whether social capital is associated with change in the adoption levels documented across the ten-year period. The paper concludes by suggesting that the effect of social capital is substantially reduced in 2010 as a consequence of institutional network dynamics featured in the theory of isomorphic change.