Reply to Dow: Party Positions, Votes and the Mediating Role of Electoral Systems?

Abstract

The proposed relationship between electoral systems and party extremism assumes that electoral systems mediate the relationship between party proximity (to the mean voter position) and vote share. In disproportional systems, parties are expected to gain greater electoral rewards for adopting moderate positions than in proportional systems. Following Jay Dow in this issue, I re-analyse the Comparative Study of Electoral Systems (CSES) data to directly evaluate the hypothesized mediating role of electoral systems in explaining party vote share. 1 These analyses do not support the finding that electoral systems mediate the relationship between party proximity and vote share. This finding suggests that further exploration is necessary to understand the relationship between electoral systems and party positioning. To review, in 2001, Jay Dow published spatial mappings of the Dutch, Israeli, Canadian and French party systems and concluded that ‘parties in the majoritarian systems are located significantly closer to the center of the distribution of voters than those in proportional systems’. 2 Inspired by Dow, I then explored the same relationship between electoral system proportionality and average party extremism in eighteen countries. 3 Parties competing in proportional electoral systems were expected, on average, to adopt more extreme policy positions than their counterparts competing in disproportional systems. After analysing eighteen democracies, however, I reported that there was no evidence that electoral systems affect parties’ tendencies to propose extreme or moderate policy positions. Jay Dow analyses the same relationship in thirty-one countries using more recent data from the Comparative Study of Electoral Systems (CSES), 4 and he reconfirms the conclusions he reports in his 2001 article that proportional electoral systems promote party extremism, and disproportional systems are more compact. I do not question the conclusions Dow reports: the empirical findings stand. If this is the case, the question naturally turns to what accounts for the difference in findings. Earlier in the issue, Dow accurately targets explanations for the differences. These are based on time-period, data and groups of countries. Since I agree that these are the likely candidates, and I do not take issue with Dow’s empirical findings, I wish to push the argument forward by turning the