Writing in the late 1970s, Sten Berglund and Ulf Lindström argued that Scandinavian party systems were often seen as 'ultra stable' (Berglund and Lindström 1978: 74), a view that was certainly justified between 1945 and the early 1970s. However, the general election of 1973 in Denmark signalled a new era of instability as the three major parties saw their aggregate share of the vote slashed from 73 to 47 per cent (Worre 1978 : 13). It was not long before similar developments became visible in Norway, to some extent in Finland, and (a little later) in Sweden.
The main political actors in the Scandinavian democracies are organized around conflicts between labour and capital, and the rural peripheries and urban centres (Rokkan 1987 : 81-95). As these cleavages were already well established by the 1920s, Stein Rokkan famously asserted that such party systems were 'frozen' in the 1960s (Lipset and Rokkan 1967 : 50). The five party families of the classic Scandinavian model (social democracy, conservatism, liberalism, agrarian 'centrism', and communism) are deeply anchored in their social bases, and class in particular has been a more important determinant of party loyalty than in other west European democracies (Rose 1974 : 3-25; Uusitalo 1975 ; Worre 1980 : 299-320). However, this strong orientation towards class politics has not resulted in revolutionary acts, except in Finland. Rather, a marked proclivity for accommodation and compromise has located the Scandinavian polities close to Lijphart's ideal type of consensus democracy (Lijphart 1984 : 21-36). Party leaders have displayed a commitment to national unity and democratic principles despite the presence of deep social cleavages. In particular, the mutual tolerance and moderation that parties typically accord each other in consensus democracies (Lijphart 1977 : 53-5) has resulted in the creation of an extensive and well-known mixed welfare economy (Erikson et al. 1987 : vii-ix).
However, the classic five-party model no longer provides a comprehensive account of party politics in Scandinavia: since the early 1970s a variety of other