This chapter starts with an account of the strategies of regional-nationalist parties with respect to the design, institutionalization, and functioning of the new state institutions. It classifies the different types of subnational party systems which have emerged in the seventeen comunidades autonomas so far, and analyse their implications for conflict regulation. The chapter examines how far these parties have been able to penetrate regional societies, and have managed to consolidate themselves. A major determinant of democratic consolidation hence lies in the nature, as well as in the level of polarization. Polarized conflict in general is enhanced by a high and increasing level of fragmentation of the political forces. The institutionalization of pre-regional governments from 1977 onwards by governmental decree provoked different reactions on the part of regional-nationalist parties. By 1977/8, the beginnings of terrorist separatism could be found in territories other than just the Basque Country, and regional-nationalist parties had to take positions with regard to their operations in public.