ABSTRACT
The analysis of cleavage structures in the preceding chapter allows us to understand why the goals for which people are most likely to mobilize differ from country to country, but it does not tell us much about the absolute levels and the action repertories of political mobilization. To explain these characteristics of political mobilization, we shall introduce two additional sets of elements of political opportunity structures (POS): the formal institutional structure of the political system and the informal procedures and prevailing strategies of political elites in dealing with challengers. Just like the national conflict structures, these two additional sets of elements constitute relatively stable elements of the political context of social movements. They are deeply embedded in the political heritage of a given political system and, from the point of view of the mobilizing social movements, they are essentially fixed and given. As such, these aspects of the political context are to be distinguished from the more volatile, conjunctural, or shifting ones, which will be the subject of the next chapter. The relevance of the conceptual distinction between more stable and more conjunctural elements of the political opportunity structure has been pointed out by several authors (Duyvendak and Koop-mans 1989; Rucht 1990b; Della Porta and Rucht 1991; Gamson and Meyer 1995).
