How Democratic Experience and Party System Development Condition the Effect of Electoral Rules on Strategic Defection

Abstract

In Chapter 4, we showed that there is significant variation in the number of parties under different electoral rules and political contexts, but we did not demonstrate the mechanisms – such as strategic defection by voters and elites – that underpin the different results we found. In Chapter 5, we began to show how rules and context shape strategic defection by voters under SMD rules, but the existence of a “personal” vote often obscured our view of much of the strategic voting that probably did occur. In this chapter, we introduce a different approach, which we use to highlight more directly how political context – most notably, democratic experience and party system development – conditions the impact of SMD rules on strategic defection in mixed-member electoral systems. Specifically, we use Cox's (e.g., 1997) “SF ratio” measure (usually the vote total of the third-place contestant [the “ S econd loser”] divided by the vote total of the second-place contestant [the “ F irst loser’]) to help draw inferences about strategic defection under particular electoral rules. As we do throughout this book, we use mixed-member systems to gain analytical leverage on electoral system effects. In this chapter we examine patterns of strategic defection in mixed-member systems in 41 elections in 11 different countries, considering how SF ratio patterns within a given country differ between the SMD and PR tiers of mixed-member systems. We show how SF ratio patterns in SMDs – unlike those in PR – often highlight the presence of strategic behavior, presumably because many voters and elites, when facing a competitive district race, transfer their support from candidates/parties who are unlikely to win to one of the top two contestants.