Preferential voting and state elections in South Australia

There will be state elections in Victoria, New South Wales and Queensland over the coming few months and in each of these states there is public discussion of whether their preferential voting systems would cope with an election at which there could be three, rather than two, major parties. In Victoria, where a full preferential count is used, voters must mark a preference for every candidate and the Liberal Party has been internally divided over whether to direct its supporters to out Labor or the Greens last on their ballot papers. Optional preferential voting would allow the parties to avoid that question, but in New South Wales and Queensland where optional preferential is used, the state Labor Parties are worried that they will lose seats if Greens voters Just Vote One and do not pass on their preferences. So optional preferential voting is being reviewed in Queensland and may be examined in New South Wales too. Like Victoria (and the Commonwealth) South Australia uses full preferential voting, but an optional preferential system is suggested here from time to time. So this paper looks at why preferential voting was introduced into South Australia’s electoral system, as one of a series of electoral changes that took place during the first half of the twentieth century. The paper considers the way that preferential voting has operated with other components of the electoral system, including single-member electorates, to shape politics in this State into a two party contest and to maintain it in that form. Then the paper uses the current election preparations in Victoria to look at the stresses on full preferential voting systems that arise when a political system seems to be moving from a two-party to a three-party system. The paper’s final section looks at optional preferential voting, which could be viewed as a solution to the parties’ problem of deciding where to direct their preferences in a three-way contest. New South Wales and Queensland both use optional preferential voting at state elections, and voters in those states can vote for just one candidate or can show preferences. At least in Queensland, optional preferential voting has not collapsed into a first-past-the-post system, and between 30% and half of all voters across Queensland do still complete a full ballot, especially in marginal seats. While optional preferential voting might solve the major parties’ preferencing dilemma, it carries its own problems: it is less successful than full preferential voting at amalgamating support, so Labor governments in both Queensland and New South Wales are currently worried that Greens candidates could reduce Labor’s first preference vote and then refuse to send their preferences back again. From time to time an optional preferential ballot is advocated in South Australia. Introducing it here would require a bigger change than was needed interstate, because South Australia’s electoral districts boundary redistribution process incorporates a fairness requirement which effectively requires a full preferential ballot