INTRODUCTION

Understanding Italian politics in terms of coalition theory has proved very difficult. From the office-seeking perspective, the common occurrence of both minority and surplus coalitions during the 1970s and the 1980s seemed puzzling (Axelrod, 1980; Laver and Schofield, 1990; Strom, 1990). Other writers have been intrigued by the apparent instability of Italian coalition governments during this same period (Sartori, 1976; Pridham, 1987). The theoretical challenge has become even harder after the institutional upheaval of the early 1990s. So much has changed in terms of electoral rule, party alignment, and party composition that it has been hard to follow, let alone explain.

Recently, Mershon (1996a,b, 2002) has made a significant contribution to the study of Italian politics by combining a theoretical approach with careful data analysis. Our own theoretical model of multiparty politics is offered as an extension of Mershon's earlier work.

Different sources of data are used in this chapter. For party policy positions before 1996 we rely on the most updated version of the Comparative Manifesto Project (CMP) (Budge et al., 2001). The methodological status of the CMP data set, obtained via content analysis of party platforms, has been challenged on various grounds. First, the CMP research strategy is meant to ascertain salience of issues rather than party positions on those issues (Laver, 2001). Second, party positions derived from the content analysis of party platforms do not necessarily coincide with voter perceptions of these positions. We use the CMP analyses only to give an approximate indication of party positions prior to 1996. For the 1996 election, we use original data obtained by Giannetti and Sened (2004).