Explaining party systems The role of electoral systems

Core explanations Party systems are a product of cleavage and cleavage structure OR Electoral systems shape party systems

Impact of cleavages Cleavage structure matters, but.. Not all cleavages are politicized or organized Some parties organize around cleavages (cleavage-based parties) while others try to bridge or blur them What parties and other entities do makes a difference

Alternate supposition: Electoral systems determine the number of parties (stronger version) OR Electoral systems influence the number of parties (more muted, weaker version)

The impact of electoral laws: Duverger’s law: –Single member plurality (SMP) > two party system –PR > multiparty system Is it valid? Factors to consider: –District magnitude –Effective thresholds

Varieties of electoral laws: District systems: –Single member plurality (SMP, first past the post) –Single member majority: Double ballot or runoff systems – e.g. France –Abs. majority required on 1 st ballot; lower candidates dropped –Plurality on 2 nd ballot PR –Single transferable vote (STV) – used in Ireland, Malta, proposed for British Columbia –List systems

Single transferable vote (STV) Multi-member districts (in Ireland 3-4 members) Voters express 1 st, 2 nd. 3rd preferences To be elected a candidate must –Secure a minimum quota: Droop quota = V/(s + 1) –Surplus votes for winning candidates transferred to 2 nd choices, candidates securing quota are elected… –Surplus votes transferred again. –If no candidate has a surplus, the lowest candidate is eliminated and his/her votes transferred –Process continues until all seats are filled

PR List systems and their variants: Impact of district magnitude Counting formulas –Highest averages –Highest remainders –St. Lague system (Scandinavia – uses special divisors Pooling arrangements; tiers – e.g. Denmark, Sweden –to deal with remainders Formal Thresholds: –Germany 5% –Sweden 4% –Denmark 2%

Alternate member (AMS) or mixed- member proportional systems (MMP) Germany: Half the Bundestag elected in single member districts, via SMP Second half elected in 2 nd, simultaneous ballot: Results of 2 nd ballot used to make the final distribution of seats proportional to the vote received by parties which have either –won 5% of the vote in the second ballot or –won 3 seats on the first (constituency) ballot

New Zealand