This paper discusses the effects of high speed rail networks deployment on the dynamics of political and territorial organization in Spain. It aims to analyse the interactions between the development of high speed rail and the interplay of institutional relations at three levels: state, autonomous communities and cities (at a metropolitan level). The Spanish institution-building context gives significant weight to autonomy. The high-speed network was developed in Spain according to a radial scheme that was supposed to connect Madrid with the 19 provincial capitals. This configuration involves a nervous bilateral relationship between the government and the regional and local authorities. The "Mediterranean corridor" project enters the Spanish high speed in an axial pattern, along the coast. The expectations created by the arrival of the AVE (Spanish high speed) in Mediterranean cities such as Valencia, leads political actors to increase horizontal partnerships with neighbour jurisdictions and alliances with different institutional levels. This development causes significant changes in the relations between political levels. In this "Nation of nations", the AVE is operating new politician alliances, creating new geopolitical "visions" and changing institutional practices. It is also the developing tool of maybe quiet, but decisive shifts of major institutional and operational frameworks of territorial government.