Political parties in Western democracies are under pressure. A variety of social, cultural and economic forces have undermined their traditional organizational and electoral practices, forcing them to change their strategies of electoral mobilization. Although the strength of these pressures varies across democratic states, and some parties are coping rather better than others, several major European parties have fundamentally changed the way they respond to their electorates over the last two or three decades. The case I will examine in this chapter, Italy, is a rather extreme example of this phenomenon. In the immediate post-war period, Italian politics was dominated by the sharp division between Communism and conservative Catholicism, represented by two parties that carried out the 'classic form' of interest aggregation. The left electorate was largely represented by the Communist Party (PCI), a classic mass workers' and peasants' party, and the Catholic centre and right by the Christian Democrats (DC), whose mobilization strategy combined traditional clientelism and close co-operation with the Catholic Church. The 'imperfect two-party system' (Galli 1966) structured around these parties reflected a divided and complex society in which political tensions were not always expressed through democratic channels. The gradual decline of Christian Democracy and the easing of the class and religious cleavages brought new forms of response from the existing parties and various adaptations to the governing coalitions, but the essential features of the party system showed a significant degree of stability. All this changed in the 1990s, as the major parties either split, disintegrated or even disappeared, and completely new parties emerged, such as the populist Northern League and Forza Italia, electoral vehicle of tycoon Silvio Berlusconi. This amounted to perhaps the most comprehensive overhaul of political representation in post-war West European history: the electoral volatility score for the 1992-94 period was 41.9 per cent.
Even before these dramatic changes, accounts of the post-war Italian political system had tended to stress its turbulence and instability. Italy was an important empirical inspiration for Sartori's conceptualization of 'polarized pluralism', a party system characterized by high levels of ideo-