In this paper we analyse the successful local/regional opposition to a proposed new town north of the Dutch city Leiden in terms of pathways, sites and techniques of object formation. In the struggle over spatial plans and policies, new objects are constructed and played out. In some cases, the new objects became institutionalized and codified future development in the region. We focus on the strategic role of the construction of heritage and nature in the planning process, concepts utilized by opponents of the urban plans. Revisiting Foucault's concepts of power/knowledge and discourse, we present a detailed analysis of the process of emergence, solidifying and institutional embedding of new forms of heritage and nature as new discursive objects. We argue that such a retour à Foucault is important, allowing for an elucidation of object formation, still understudied in planning and governance studies.