Australian politics circa 2006

By Warren Smith & Jan Kok

We shall here argue that IRV leads to 2-party domination, and Australia is evidence of that. However, the situation is somewhat more complicated than that; Australia uses several voting systems for different purposes – IRV is only one of them – and because of the other multiparty-genic nature of some of the other systems (especially 10-winner reweighted-STV PR for Senators) Australia is not entirely 2-party dominated.

Australia uses these four voting systems (compulsory voting enacted 1924):

  1. First-Past-The-Post (also called Simple Majority; single winner)
  2. Instant Runoff Voting (IRV, also called preferential voting; single winner) [Australian House of representatives; system enacted 1918]
  3. Multiwinner Proportional Representation based on Hare/Droop reweighted single transferable vote (STV) [Australian Senate]. Originally each state elected 6 senators but in 1949 that was changed to 10 and reweighting was added to the STV to make it become more proportional. Voting was made compulsory (enforced by fine) in 1924 and in 1934 it was made compulsory for voters to list all preferences.
  4. Multiwinner Hare-Clark Proportional Representation STV system [Tasmanian House of Assembly and the ACT Legislative Assembly]

According to the Australian analysts at the "Disadvantages of the Preferential [IRV] System" are

  1. It is more complicated to administer and count.
  2. It can produce a higher level of informal voting.
  3. It promotes a two-party system to the detriment of minor parties and independents.
  4. Voters are forced to express a preference for candidates they may not wish to support in any way. (The use of optional preferential voting, as used in New South Wales State elections, is a solution to this problem.)

According to Wikipedia, the minor parties (e.g. The Australian Democrats, Greens, One Nation, Family First, Christian Democrats) are often able to hold Senate seats thanks to the multiwinner PR system used to elect it, but have usually been unable to hold House seats thanks to the fact that they are elected using IRV. As I write this in 2004-2007 the total number of House seats owned by these parties is zero out of 150. (There is a seat owned by CLP member Dave Tollner, but the County Liberal Party is really the Liberal/National party branch in the Northern Territories. There are also 3 seats held by unaffiliated MPs, all of whom only got there because they used to be major-party members originally.) The total party composition of the House is {Liberal=74, National=12, CLP=1}, Labour=60.) The total party composition of the Senate is {Liberals=33, Nationals=5, CLP=1}, Labour=27, AD=4, Greens=4, Family First=1 – much less 2-party dominated. (The "LibNat" members are shown in {these brackets}.). In past years the situation has been similar:

Year Party composition of House ENPPA ENPPB
1963 Labour=41.0%, National=16.4%, Liberal=42.6%, rest=0.0% 1.9 2.7
1972 Labour=53.6%, National=16.0%, Liberal=30.4%, rest=0.0% 2.0 2.5
1980 Labour=40.8%, National=16.0%, Liberal=43.2%, rest=0.0% 1.9 2.6
1993 Labour=54.4%, National=10.9%, Liberal=33.3%, Indep=1.4% 2.0 2.4
2004 Labour=40.0%, National+CLP=8.7%, Liberal=50.0%, rest=0.0% & Indep=2.0% 2.0 2.4
Party composition of Australian House through time. ("Country" party now renamed "National" party.) ENPP="Effective Number of Political Parties", which is the reciprocal of the sum of the squares of the party seat-fractions, [A] is if the Nationals and Liberals are regarded as a single "party" – which incidentally is how regards them (they call them the "LPA/NPA" and Australians themselves often call them the "NatLibs" in colloquial conversation; also see wikipedia, which refers to the NatLibs as "the coalition") – and [B] is if they are regarded as separate.

There evidently are three major parties, but there really are only two because the National Party is really essentially a junior partner of the (misnamed) Liberal Party and always forms a coalition with it and always elects a Liberal-party PM if that is achievable; hence a vote for the Nationals is essentially a vote for the Liberals. Indeed many Australians and Commentators refer to them as the "NatLibs" or "LibNats" because they are "really" one party. Indeed they submitted a joint "above the line" (party vote-ranking recommendation) in the last (2007) elections, and they almost always arrange never to run candidates against each other.

Opposed to the NatLibs is the Labour party.

Every one of the 17 prime ministers since 1923 has been from one of the top two parties provided we lump the National party with the Liberals. (Asterisks: The Nationalist party was absorbed into the UAP in 1931, and the UAP was absorbed into the Liberal party in 1943. The "Country" party later was renamed the Nationals.) Since 1941 the prime minister has been either a Labor or Liberal Party member all but one year. That's because, in all but rare instances, the Governor-General appoints the leader of the majority party in the House of Representatives to the post.

Independents do better than third-party members in Australia (like the USA)

I just looked through the (late 2006) membership of the Australian House of Representatives, and the Legislative Assemblies. Shown below are legislative bodies elected by Preferential Voting (IRV), the number of independent members, and the total number of members.

Australian House of Representatives 3/150
New South Wales Legislative Assembly 7/93
Queensland Legislative Assembly 4/89 *
South Australian House of Assembly 3/47
Tasmanian Legislative Council 10/15 **
Victorian Legislative Assembly 2/88
Western Australian Legislative Assembly 2/57
Northern Territory Legislative Assembly 2/25

Notes:    * = also 1 member of One Nation party.
** = Tasmania is "upside-down" – the Legislative Council is the upper house, as with other states, but it's the upper house that uses single-member districts.

We conclude that third parties are almost totally unsuccessful in Australian IRV seats (1 seat out of 564) but independents have won 33 seats (5%). This is similar to the USA, where Independents also outnumber third-party members in statehouses and federal government seats. In the USA, there are zero third party congressmen but (after the 2006 elections) two independents out of the 553 total (namely Lieberman & Sanders). Sanders replaces Jeffords who also was independent.

USA third parties are so weak that joining them does not really help. For example Lieberman's 2004 Senate campaign in Connecticut (former Democrat running independent) had more funding by far than the entirety of the largest third party in the USA, nationwide. Sanders achieved no success running third party but later, with the aid of some uncontested and opposition-vote-split elections, rose to prominence all as an Independent. Lieberman and Jeffords both were major party members their whole political careers (Dem & Repub respectively) until, as Senators, they left their parties due to disputes. This did not prevent their re-election as Independents.

According to Australians who helped us, the Independents usually got there, just like in the USA, by having disputes with their major parties causing them to part ways. (And in many cases these divorces were only temporary.)

Let's make that simpler: Australia's IRV system clearly yields duopoly

In the last three Australian (Central government) House election cycles, zero third-party members were elected in 2001. Then zero in 2004. Then it happened again in 2007 with the NatLibs getting 65 and Labor 83 seats, with 2 seats going to unaffiliated MPs. (150-member house.)

This was not because other parties did not run candidates. On the contrary they contested every one of those 450 races with an average of over 7 candidates running for each seat. Nor is it because those other parties were weak. On the contrary, third parties can and do win seats in the Australian Senate (elected via a different system) and hence are far stronger than in, say, the USA.

IRV versus PR seatholders

The composition of IRV seatholders in Australia is very biased against third parties: examining all 564 statehouse & federal IRV seats we found only a single one occupied by a third party.

But the PR seatholders are much more third-party. e.g, of the 76 Australian senate seats (post-election 2004) we find that 9 were third-party members (4 Green, 1 Family-First, 4 Dems). That is 67 times larger third-party seat occupancy rate in PR than in IRV seats.

Meaning (9/76) : (1/564) is 67:1.

So it should be obvious that IRV has a massively discriminatory effect against third parties in Australia.


We conclude that the IRV system in Australia has led (and in the opinion of the Australians themselves has led) to 2-party domination, although it could perhaps be argued it is 3-party domination depending on how independent you regard the Nationals as being from the Liberals, and also depending on how significantly you view their present 7.6% seat share in the Senate+House combined.

However, this 2-party domination presently is slightly less severe than in the USA, probably mostly due to the moderating effect of Australia's simultaneous use of 10-winner PR reweighted-STV for Senators. (Australian third parties have no trouble electing their members as senators, with e.g. 4 Greens, 4 Australian Democrats, and one Family First senator incoming in 2008 out of the 76 total. That is because senators are not elected using IRV. They are elected using multiwinner PR elections.) But perhaps arguably, it's because IRV leads to a slightly less powerful kind of 2-party dominance than does plurality – but we think mainly because Australian politicians feel a little bit more willing to drop out of (or be kicked out of) their major parties than US politicians, resulting in a slightly higher percentage of "independents." In any case, alternative parties in Australia are dissatisfied with IRV.

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