This article compares the relationship between national embeddedness and metropolitan development in the Detroit and Nagoya auto regions. Based upon literature, descriptive data and in-depth interviews with 140 development officials in these 2 regions, it finds that, over the past 30 years, the US governmental system, its national approach to development and a lack of institutional support for metropolitan planning, have produced fiercely competitive interlocal relations. These elements have also exacerbated conditions of uneven metropolitan development in the Detroit auto region. Conversely, it argues that Japan's embedded autonomy has produced extremely co-operative intermunicipal relations and has helped to facilitate relatively balanced growth in the Nagoya auto region, during this same period. In other words, despite arguments against it, the spatial configurations of metropolitan areas in the US and Japan continue to be embedded or nested within their national (and sub-national) contexts.