The Swiss party system has become significantly more polarized during the last two decades. The Swiss People’s Party has made impressive electoral gains since the early 1990s. At the same time, the major left-wing party, the Social-Democrats, could hold to its vote share of the late 1980s or improve upon it, while the Greens have made important gains. One can thus observe the formation of two poles, with strongly divergent ideological positions. These party blocs have strengthened at the expense of the major centre and centre-right parties, the Christian-Democrats and the Liberals, which have suffered significant electoral losses in recent national elections.
What do these developments tell us about the motivations of the Swiss electorate?
A common interpretation is that voters, too, have become more polarized. The relatively weak results of the centre parties in recent elections would be a direct reflection of the comparatively high degree of ideological polarization among Swiss citizens. Given the magnitude and speed of the changes in the party landscape, this would mean that the ideological preferences of Swiss voters have been transformed to an impressive degree over a relatively short period of time.
In a recent analysis of the 2007 National Council elections Peter Selb and I suggest a different interpretation, by showing that many voters are guided by strategic considerations. The consensual character of Swiss democracy means that any party has only a limited influence over the government position. Voters may respond to these institutional constraints by supporting parties that are more extreme than their own preferences. This “compensatory voting” has been discussed in the literature for some years, but applications to the Swiss case have been quite limited. Our analyses show that this form of strategic voting is strong among Swiss voters.
Stronger party system polarization may thus “simply” mean that voters are becoming more strategic. A greater proportion of citizens appears to consider how their voting choice in the parliamentary elections could affect the position of the government. It is likely that such tactical considerations have become more important since 2003, when the Swiss People’s Party won a second seat in the Federal Council (the first change in the partisan make-up of the government since 1959!). During the campaign of the 2007 parliamentary elections, possible changes in the partisan composition of the Federal Council were hotly debated. Voters were thus confronted with clear incentives for compensatory voting. As the debate on the composition of the government is likely to be at least as intense in next year’s National Council elections (see for example here), we could witness even more strategic voting and further polarization in 2011.