A note about third party votes

Just another thought about today’s South Australian election (previewed here yesterday): with One Nation registering above 20% in the opinion polls, people might be wondering what the precedents are like for third parties getting results like that. How high does it have to get to be breaking records for a third party vote?

The answer depends on what you mean by a third party. Taking the simple definition of the party that comes third in an election, the top five Australian results (since the inception of the two-party system in 1910) are as follows:

Party	State	Year	Vote
National Party	Queensland	1974	27.9%
Liberal Party	Queensland	1980	26.9%
Liberal Party	Queensland	1977	25.2%
Liberal Party	Queensland	1957	23.2%
Liberal Party	Queensland	1995	22.7%

OK, so that’s not very useful. Queensland dominates the rankings – it actually has 16 of the top 20 – because of its historically strong National Party (previously Country Party) in the days before amalgamation. Either it knocks the Liberals into third place, or records a high third-place finish itself.

So what about the top five results outside of Queensland? That produces this table:

Party	State	Year	Vote
Greens	Tasmania	2010	21.6%
Country Party	Victoria	1945	18.7%
Liberal Movement	South Australia	1975	18.3%
Greens	Tasmania	2002	18.1%
DLP	Victoria	1961	17.0%

Some impressive results there, although with widely differing outcomes. The Country Party had been in government in Victoria for most of the previous ten years; its record result was actually recorded the year it lost office. The Tasmanian Greens, in a house elected by proportional representation, won seats that matched their vote, and in 2010 were taken into coalition. But the Liberal Movement won only two seats and stayed in opposition, while the DLP in 1961 won no seats at all.

But perhaps that’s not what people mean by third parties: maybe what they’re interested in is parties outside the two-party system. In other words, parties that aren’t Labor, Liberal, Country or National, regardless of their relative finishing position. In that case, these are the top five:

Party	State	Year	Vote
Queensland Labor	Queensland	1957	23.4%
One Nation	Queensland	1998	22.7%
Greens	Tasmania	2010	21.6%
Liberal Movement	South Australia	1975	18.3%
Greens	Tasmania	2002	18.1%

The top two, both in Queensland, finished second rather than third: behind Labor in both cases, but ahead of the Liberals and Country/National parties. The Queensland Labor Party, which later became the Queensland branch of the DLP, was in government at the time, the premier and most of his ministers having been expelled in the great Labor split. They won 11 seats to official Labor’s 20, but the Coalition parties easily won government with 42 seats between them, even though in terms of votes the Liberals only came third and the Country Party fourth.

The 1998 Queensland election is of course the most obvious comparison for this year. Labor easily topped the poll with 38.9%, but its 44 seats put it only one ahead of the combined total of One Nation (11 seats), the Liberals (16.1% and nine seats) and the Nationals (15.2% and 23 seats). There were also two independents, one of whom reached agreement with Labor to allow it to govern.

South Australia, with a smaller parliament and no National Party to speak of, will probably not show quite the same complexity, but with a raft of competitive independents it’s going to be complex enough. I’ll finish with a nice summary from Kevin Bonham:

Either the Liberals or One Nation or perhaps even both could potentially do very poorly in seat terms as a result of a combination of a small number of seats available to the right and some of those seats being claimed by independents. There is some evidence in modelling that the Liberals might win more seats than One Nation off a somewhat lower primary vote, provided the gap is not too large. On the other hand, there is not a single seat I could safely chalk down as a Liberal hold prior to seeing any votes. There is scepticism from many observers about whether One Nation will win anything at all, on the grounds that in their best prospect seats the Liberal Party’s incumbents are just too entrenched, but the swing has to be somewhere. So I would think that if One Nation wins no seats or only one seat, it will be because they have underperformed their polls.