Although it is widely recognized that the number of political parties within a political system has numerous consequences for the process of policy formation and the stability of governments, less is known about the impact the number of parties may have on the relationship between parties and society. We know that the more fractionalized a system is, the more compartmentalized the competition is likely to be, with each party targeting its own core clientele (Mayer 1980). As Almond and Powell stated long ago, 'the presence of a large number of fairly small parties makes it increasingly likely that each party will merely transmit the interests of a special subculture or clientele with a minimum of aggregation' (1966:103). Few recent studies, however, have focused on how fragmentation affects the patterns of response of political parties to the electorate.
The break-up of the Union for French Democracy (UDF) in 1998 gives us an excellent opportunity to examine this question. The UDF was an important party in the French system, controlling about 109 out of 577 seats in the National Assembly at the time of its break-up, and the breakup was a serious one: the new splinter party, Liberal Democracy (DL), gathered about one-third of the former UDF members. Here we examine how this change affected the responsiveness of the political parties by focusing on two parties, the UDF, reduced to two-thirds of its former size, and the new DL. (It is recognized that it is reasonable to assume that all parties in the system were inevitably affected by such an important change in the nature of the competition, but investigating such changes would go beyond the scope of this study.) Thus, to what extent did the split alter the responsiveness of the French non-Gaullist moderate right, as represented first by the UDF, and now by the UDF and the DL?
Responsiveness of political parties can be defined as the activities they undertake to translate supporters' preferences to the political arena (Keman 1997:165-9). Political parties, however, are never simple 'transmission belts' of well-defined interests from civil society to politics. From the wide scope of interests represented by their electorate and their membership, political parties have to create a more or less coherent