Double Dissolution possibilities


Tim Andrews has written a post projecting what he thinks would happen to the Senate at a double dissolution or half senate election, concluding that either scenario would see the Greens control the balance of power, with Labor + Greens giving a majority, and no other possible combination of Labor and minor parties giving them a majority. This would have interesting policy consequences, as Labor would have a clear choice between working with Liberal or Greens, as opposed to the choice at the moment between Liberal or stitching together a deal with Greens, Xenophon and Fielding.

I don’t necessarily agree with a lot of Tim’s suggestions, but I thought it was an interesting exercise to come up with a result, so here goes.

I’m using Possum’s latest polling average, which gives 48.9% primary vote to the ALP and 36.1% primary vote to the Liberals, to predict swings between those two parties. This gives a 5.5% swing to the ALP and a 5.7% swing away from the Coalition, although this may vary, and I will also use common sense when plugging those numbers in.

I’m projecting the following results. For a half-Senate election:

  • ALP 36
  • LIB 29 (inc. CLP)
  • GRN 8
  • NAT 2
  • Xenophon

And for a double dissolution

  • ALP 36
  • LIB 27 (inc. CLP)
  • GRN 8
  • NAT 2
  • Other 3 (inc. 2 Xenophon and right-wing Queensland senator)

Full state-by-state breakdowns over the fold.

New South Wales – The problem for the Greens in NSW is that the ALP vote is so high when they are in government that the Greens get locked out. A 5% swing to the ALP will put them on 47%, with the Coalition dropping to 34%. The combined ALP-Greens vote would then add up to four quotas, giving the Greens a seat in a half-senate election, for a total of 3-2-1. Assuming that Fiona Nash remains third on the ticket, as in 2004, this would result in a loss of one National seat to the Greens.

A double dissolution would see the ALP win six, the Greens win one and the Coalition win four, with the last seat being a contest between a Liberal and the CDP. I would tip the Liberal to win, so I’ll count it as that, resulting in 6-5-1.

Victoria – Again, a 5% swing to the ALP would solidify their third half-senate seat and give them six DD quotas. The swing would reduce the Coalition to 34%, with the Greens on 10% (likely higher if current polls are to be believed). This would probably result in a 3-2-1 split in a half-senate election and a 6-5-1 split in a double dissolution.

Queensland – Again, a similar level of ALP and Coalition votes would see the ALP winning a solid 3 in a half-senate election and 6 in a double dissolution, with the Coalition struggling for its 3rd and 5th respectively. In the case of a half-senate election, the third Liberal would be on 6%, behind the Greens on 7.3%, however you would expect that preferences from the conservatives who gave 4% to Pauline Hanson and 2% to Family First would put the Liberal on top. The 2% surplus from Labor to the Greens would probably not be enough, resulting in 3-3 (with Barnaby Joyce’s seat being lost, and Joyce either moving to the House of Representatives or taking Ron Boswell’s seat. In the case of a double dissolution, the result would be 6-4-1, with the last seat a race between a fifth Coalition candidate, Pauline Hanson if she runs, and Family First if Hanson does not run. I’m going to notch it up to “right wing minor party”, for a total of 6-4-1-1. It’s also worth noting that if the Greens can get over 7.7% their senator would gain a six year term, rather than the three-year term that would go to a right-wing minor party candidate elected on preferences.

Western Australia – The Liberal Party won by a 10% margin in WA in 2007. If the swing was uniform, it would result in the Liberals and the ALP both polling around 41%, putting them both close to a full quota. While the WA Greens polled 9.3%, 10% would not be unreasonable with a sitting Senator running in 2010. However, you’d have to project a result of 3-3-0. In the case of a double dissolution, Labor and Liberal would each win 5, with the Greens winning one, and all three parties having about 3% of a surplus, with other parties having small amounts, and you would have to say that the result would likely be Liberal 6, Labor 5, Greens 1, although it could easily go another way.

South Australia – Tim assumes that Nick Xenophon will run a ticket in a half-senate election, even though he would not be up for election. I disagree, so I’m assuming he does not run. This makes it harder to predict where his 14.8% would go. I’m gonna say that 6% would go to each major party, with 2% going to the Greens and 1% to Family First. Once you factor in the major party swings, you come up with 46% ALP, 36% Liberal, 8.5% Greens, 4% Family First. In the case of a half-senate election, this would produce 3 ALP, 2 Liberals and a contest between a Liberal on 8% surplus and a Green on 8.5%. With a 4% surplus from the ALP I would predict a victory for the Green, for a total of 3-2-1.

In the case of a double dissolution, I would predict that Xenophon’s vote would fall slightly due to him likely having helped trigger the early election, to 14%. The result would be 5 ALP, 4 Liberal, 2 Xenophon and 1 Green.

Tasmania – A half-senate election would result in a split of 3 Labor, 2 Liberal and 1 Green. In the case of a double dissolution, however, it becomes more interesting. Labor wins 6 seats, on 45%. Liberals win four seats, on 32%, while the Greens on 18% win at least two. It’s interesting to note that if the Greens gain a greater swing at the expense of Labor a possibility of a third Green is not out of the question, but I’m still projecting 6-4-2.

Territories – The Northern Territory is no contest, with the ALP and CLP each winning one seat in any scenario. The ACT is more interesting. The race is effectively between the Liberals and a coalition of Labor, Greens and other smaller parties, meaning that an increase in the Labor vote at the expense of Liberals directly benefits the second left-wing candidate. As long as the Greens stay ahead of the second Labor candidate, any swing to the ALP could help knock off the Liberal. With Gary Humphries polling 34.2% in 2007, any swing of at least 2% would be enough to elect a Green. Considering that the polls currently project a 5% swing to the ALP, this would be enough. However it’s worth noting that Kerrie Tucker would be unlikely to run again, and a less high-profile candidate would possibly lose votes for the Greens. Most of the Greens’ best candidates in the ACT have been swallowed by the ACT Assembly and won’t want to jump ship to federal so soon after starting (although some of them may make great Senate candidates further down the road), so the ACT Greens are running low on talent. On the other hand, if most of these votes are lost to the ALP, they will be recovered as preferences.

Liked it? Take a second to support the Tally Room on Patreon!


  1. Wow, what a fascinating post. A double dissolution would be most interesting to observe from a psephological/political junkie point of view.

  2. I find it amusing that although our means of getting there were rather different, the results we both came up with were almost identical, particularly for the DD (where there was only 1 senator different).

Comments are closed.