Institutional capacity to integrate ‘radical’ perspectives on sustainability in small municipalities: experiences from Sweden

•This study explores the role of the local community level in a transition to long term sustainable development.•It places a focus on institutional capacity (frames of reference, relational resources and mobilization capacity)•Empirical work was carried out in two small Swedish municipalities: Alingsås and Övertorneå.•The work illustrates the importance of individuals with often overlapping roles.•The work identifies the need for a broader consensus that sustainable development requires radical change.