Who will control the next Senate?

As we slowly approach the next Australian federal election, the next Senate may be more ideologically divided than the current one.

Sometime before May 2022, Australia will have a federal election. As well as voting for the House of Representatives, around half of the Senate will be up for election. This post will provide an overview of the current state of the Senate and consider possible scenarios for the make-up of the next Senate.

This post shouldn’t be red as a forecast – merely an assessment of different scenarios at this moment in time.

Senate basics

First, the basics. There are 76 seats in the Senate. 72 senators serve fixed six-year terms, with half of these seats up for election every three years. Each state gets 12 senators. 4 senators represent the ACT and the NT, who each get two senators and face voters every three years.

This means that the term of half the state senators will expire on June 30 2022, while the other half of the state senators (who were elected at the 2019 election) will continue serving until June 30 2025.

39 seats are required to pass legislation. It is extremely rare for one party to win a majority in the Senate, so governments are required to negotiate with minor parties and independents (crossbenchers) to pass legislation. If these crossbenchers are ideologically aligned with the government or centrist, passing legislation is usually manageable with a bit of horse-trading. If not, passing laws can be more challenging.

To summarise: there are 36 state senators serving until 2022, 36 state senators serving until 2025 and 4 territory senators serving until 2022. Confused? Okay!

A note on the territories

Every Senate election in the ACT and NT has always resulted in the Coalition and Labor winning one seat each in each territory. Although this is not guaranteed into the future, the result has never been particularly close in the past. In the absence of polling showing a collapse in either party’s support in the ACT and NT, I am going to assume that this result will be repeated at the next election. As such, to simplify the following analysis, I will not mention the territories again.

So let’s start this analysis by looking at the 36 Senators who we know will be in office until 2025 and will serve in the next Senate regardless of the next election result.*

The 2019 result: Senators serving until 2025

These 36 senators were all elected at the 2019 election. This election was relatively close, with the Coalition winning the two-party preferred vote by a couple of points. The seat results by party were:

  • Coalition: 17
  • Labor: 11
  • Greens: 6
  • Jacqui Lambie: 1
  • One Nation: 1

The sum ideological split is 18 right (Coalition plus One Nation), 17 left (Labor plus Greens) and the hard-to-classify Lambie.

Let’s consider the results by state. In NSW, VIC, WA and SA, the seat breakdown was very straightforward, with three seats going to the right (all to the Coalition) and three seats going to the left (2 Labor, 1 Greens). I will call this the ‘default’ result.

In Tasmania, the left won three seats but the right only won two seats, with Lambie taking away enough of the right’s vote to win a seat herself.

In Queensland, the Labor vote collapsed to such an extent that the left only won two seats (one Labor and one Greens). The right won four seats, with the Coalition winning three and One Nation winning one. I have summarised all this in the table below.

Table 1. Senate results by state in 2019.

StateLNPALPGRNONLambieRight-left-other split

What does this tell us? Unless a minor party or independent has a relatively high primary vote (eg. Lambie in TAS) or a major party’s primary vote collapses (eg. Labor in QLD), the most likely result is each state electing three senators from the right and three senators from the left.

Scenario 1: A three-three ideological split

With a three-three split being the ‘default’ result, let’s consider the scenario where this result eventuates in every state at the next election.

If each state does in fact elect three senators from the right and three from the left, this means that:

  • The right will hold exactly half the seats in the Senate.
  • The left will be one seat short of holding half the seats.
  • Lambie will be the sole non-ideologically aligned senator.

In this scenario, Lambie will be extremely significant. If she votes with the right, she can pass bills. If she votes with the left, she can deadlock the Senate.

If this scenario eventuates, it will have major implications depending on whether the Coalition or Labor form the next government (more about this in ‘Summing Up’).

Of course, this is only one possible Senate scenario. There are at least two other plausible scenarios:

  • The left or right manage to win four seats in one or more states.
  • A centrist or non-aligned candidate is elected in one or more states.

Let’s consider these alternative scenarios.

Scenario 2: A 4-2 ideological split

Which state is most likely to deliver a 4-2 ideological split? The Coalition and One Nation achieved this in Queensland in 2019 and could do so again. And after WA Premier Mark McGowan’s truly crushing election victory in March, it is tempting to think Labor and the Greens could win 4-2 in WA.

But federal polling shows things are much closer. Newspoll’s latest quarterly breakdowns for each state (covering the period January to March) do not show either Labor or the Coalition with substantial leads in any states.** In two-party preferred terms, the polling in NSW, VIC, QLD and WA shows a result of between 53-47% in the Coalition’s favour to 53-47% in Labor’s favour. In SA, Labor is leading 55-45%.

What does this mean? At this point in time, it doesn’t appear that the left or right has anything like the dominance needed in any state to achieve a 4-2 senate result. SA is the only state that comes close – but even a 55-45% split is unlikely to be enough.

Of course, this situation may change over the next 12 months – the Coalition or Labor may experience a surge in support or the polling could be wrong – but I think at this point it is fair to consider a 4-2 split in any state unlikely.

Scenario 3: Minor parties and independents

But what about the prospects of minor parties and independents?

Since the removal of undemocratic group voting tickets in the lead-up to the 2016 election, which enabled minor parties to win seats despite getting hardly any votes, getting elected requires actually winning a reasonably large chunk of votes. In 2019, the only minor parties elected in any state with a primary vote of below 10% were the Greens in NSW (8.7%), Lambie in TAS (8.9%) and the Greens in QLD (9.9%). The largest vote for a minor party that did not win a seat was One Nation in WA (5.9%).

Considering there has only been one half-Senate election under the new voting system, it is risky to make sweeping generalisations. But I think we can tentatively say that a minor party has a good chance of getting elected with a primary vote of over 8% while it is very hard to get elected with a primary vote under 6%. The 6-8% range is a bit of a grey zone.

So how are the minor parties polling?

Newspoll shows the Greens polling above 10% in every state making them highly likely to win a seat in every state (if an election were held today). Conversely, One Nation is polling 4% or below in every state except QLD, where they poll 8%. So One Nation have a good chance of holding their only seat in QLD but do not look like they have much chance of winning any others.

As for other minor parties or independents, none even come close. There are currently two incumbent crossbench senators from South Australia who are both up for election. Both are centrists: Stirling Griff from the Centre Alliance and Rex Patrick, an independent formerly of the Centre Alliance. Neither of these senators are showing up in the polling and I struggle to see either of them getting elected. Neither of them seem to have much of a public profile in South Australia (at least from what I can tell). And at the 2019 election the Centre Alliance completely bombed, winning just 2.6% of the vote. Is there a bastion of support for Griff and Patrick that is hard for outsiders to see? Perhaps. Could one or both senators significantly increase their profile in the next 12 months? Perhaps. But I think the safe assumption at this point is that neither senator will be re-elected.

Which other minor parties or independents could get elected? Honestly I can’t think of any with a realistic chance. Maybe Lambie will endorse another Tasmanian candidate to run with her backing. Maybe some new independent will throw their hat into the ring and gain a significant following. But it’s anyone’s guess.

Summing up

None of this post is predictive. A LOT can happen over the next 12 months. But right now, the most likely Senate make-up after the next election appears to be 38 senators on the right (Coalition and One Nation), 37 senators on the left (Labor and Greens) and 1 Jacqui Lambie.

Both the Coalition and Labor would find this Senate a tough proposition. A Coalition Government will always need the support of either:

  • One Nation AND Lambie, or
  • Labor, or
  • The Greens

But the situation for a Labor Government would be even worse. Passing bills will require the support of either:

  • Coalition, or
  • Greens AND Lambie AND One Nation***

This could have a significant impact on a future Labor Government’s legislative program. They are not going to be proposing progressive legislation if they need to rely on the support of One Nation or the Coalition to pass it.

Perhaps Labor could tempt a Coalition MP to defect and become speaker? But now I’m really speculating.

*Unless the government calls a double dissolution election. But let’s not go there.

** Newspoll does not publish a state breakdown for Tasmania.

***If One Nation hold two seats, Labor wouldn’t need the support of Lambie in this scenario. But let’s face it, if Labor aren’t getting the support of Lambie, they aren’t going to get the support of One Nation.


Newspoll’s latest quarterly breakdowns, used in this post, show the Coalition leading 53-47 in Queensland and Western Australia, a 50-50 split in New South Wales and Labor leading 53-47 in Victoria. If this were to eventuate at the next election, this would represent a 2% swing to Labor in WA and NSW, a 5% swing to Labor in QLD and no change in VIC. This could very well give Labor a narrow majority in the House of Representatives. So a scenario where Labor forms government while the Coalition and One Nation hold a blocking majority in the Senate is not far-fetched.

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