ABSTRACT
One of the important indicators of party system change during the past few decades is the increasing promiscuity in national coalition formation (Bartolini 1998). Coalitions are indeed often formed (or supported) by new combinations of parties, including parties that are either new or that were before not considered to be governing parties. One of the explanations for this promiscuity and for these innovative combinations is the sheer presence of a large number of new parties able to attract a substantial number of voters. In the 1990s the average electoral result for parties created after 1960 in 15 West-European countries was a quite impressive 23.7 per cent (Mair 2002: 134).
