At last, the government has laid its Senate reform cards on the table with legislation introduced to Parliament yesterday. Before it was even off the presses, the bill was being met with claim, counter-claim, counter-counter-claim, and so on. According to Prime Minister Malcolm Turnbull, “the only person that will benefit from these is the voter, because the voter will determine where their preferences go”. But small party senators have decried the move as a “power grab”, a “dirty little deal” and “political trickery of the highest order”. So what gives?

What would, and wouldn’t, change?

There are two separate questions here, relating to the design of the ballot paper, and the electoral system itself. The ballot paper will continue to list parties above the line and candidates below it, but voters voting above the line will now be directed to number a minimum of six boxes (perversely, below-the-line voters will still have to number every box). Consequently, above-the-line voting will serve simply to relieve voters of the chore of numbering a party’s candidates in the order listed, rather than having them acquiesce to that party’s complete “group voting ticket”, as has been the case since the above-the-line option was introduced in 1984. But whereas the 1984 reforms were essentially a matter of ballot paper design, the new reforms will have a consequential effect on the electoral system itself, in that votes will drop out of the count at the point where a voter ceases indicating a preference. In the past, candidates who were elected to the Senate at a normal election have done so by gathering a quota equal to one-seventh of the total vote, either through primary votes or preferences. Now there won’t be enough votes left in the later stages of the count for that to happen, so the last few seats will go to whoever comes closest.

Has this been tried before?

Voters in the Australian Capital Territory are familiar with one particularly noteworthy feature of the proposed system — the fact that it doesn’t mean what it says. Ballot papers in ACT elections instruct voters to “number five boxes from 1 to 5 in the order of your choice” and to continue or not continue beyond that point according to taste. Nonetheless, ballots marked with between one and four boxes are still admitted to the count. Similarly, the legislation introduced to the Senate yesterday would amend the section of the Electoral Act relating to “marking of votes in a Senate election” by requiring that above-the-line votes have at least six boxes numbered — but it would also amend the section dealing with the formality of above-the-line votes by adding a “savings provision”, whereby above-the-line votes with five or fewer numbers would remain in the count. Regardless of which section a vote is allowed under, the result is the same: voters could simply number one box above the line and have no preferences pass on to other parties, just as they can in state upper house elections in New South Wales. This brings us to a second answer to the question: an essentially similar system has been tried before at the last four New South Wales state elections, except for the fact that the ballot paper there gives voters an accurate account of what the system will allow, and below-the-line voters may number a minimum of 15 boxes.

Why this proposal in particular?

In April 2014, a report by the Joint Standing Committee on Electoral Matters recommended following the example of New South Wales by dispensing with group voting tickets and allowing voters to number as many or as few boxes above the line as they wished. One of the attractions of this was that voters who failed to notice the change and continued numbering a single box above the line would still be casting a formal vote. However, the likelihood that the overwhelming majority of voters would indeed continue numbering one box above the line made the change quite radical in effect, since preference flows between different parties would have been all but eliminated. This cost it the support not only of Labor, whose powerbrokers discerned that Senate reform had nothing to offer them in any case, but also of the Greens, who decided that the evaporation of preferences was undesirable, either for their own sake or that of the minor party cause more broadly. To win over the Greens, and perhaps bring other crossbenchers on board, the government agreed to a minimum of six numbers as a compromise. However, this introduced the noted difficulty that the most common method of voting under the old system would be informal under the new one — hence the savings provision, and the awkward mismatch between the wording on the ballot paper and the rules of the game in practice.

Why are the Coalition, the Greens and Nick Xenophon lined up together against Labor and the micro-parties?

For both Labor and the Coalition, the outstanding fact of the proposed reforms is that they will reduce the role played by preferences, which can only be of advantage to the party with the higher primary vote. With the left-of-centre vote increasingly splitting between Labor and the Greens, that means reform will tend to benefit the Coalition more than Labor — albeit to nothing like the extent indicated by certain reports last week. For much the same reason, the issue puts the Greens and Nick Xenophon at odds with the rest of the crossbench. Since the Greens and Xenophon command sizeable primary vote support, they only stand to lose out under a system where the micro-party vote can coalesce behind the one lucky candidate who finishes ahead of the field.

Is this the end for micro-parties, preference harvesters and tablecloth ballots?

Preference harvesting will only be possible to the extent that voters consciously agree to vote as directed by their favoured party. How-to-vote cards provide an at least partially effective means of doing this, with a little over 40% of major party voters acting in accordance with their party’s instructions in the lower house. However, that’s no comfort to micro-party hopefuls, who don’t have enough volunteers to put how-to-vote cards in the hands of supporters at polling booths. To that extent, the reforms deliver the bigger parties what might be thought an unfair advantage, since only they will bring chips to the table during preference negotiations. This means the system is certain to deliver on its basic objective of preventing results like Ricky Muir’s election in Victoria from 0.5% of the vote. Having lost much of their incentive to run, micro-parties will presumably diminish in number, causing ballot papers to reduce in size. This will, in turn, diminish the number of votes cast accidentally for parties like the Liberal Democratic Party and the Democratic Labour Party. However, the evident thirst of many voters for options outside the established parties will surely find outlets that accord with the reality of the new system. Similarly minded micro-parties will have a powerful incentive to merge, and the emergence of regional mavericks like Nick Xenophon might even be actively encouraged.

Labor Senator Sam Dastyari says the reform will cause informal voting to skyrocket, but party colleague Gary Gray says this is “entirely wrong”. Who’s right?

Gary Gray is one of four Labor members on the 10-member Joint Standing Committee on Electoral Matters — which, as noted, unanimously called for the system to be reformed two years ago. By contrast, Senator Sam Dastyari led the charge against reform in the ALP, saying in May last year that it would be “complete madness for Labor to support any proposal that would risk forever preventing a progressive Senate”. On Sunday, Dastyari backed his position with an analysis that pointed to a spike in the informal rate from 3.5% to 10%. However, this assumed a system in which ballots with fewer than six boxes numbered would be deemed informal. To the extent that Dastyari has not distanced himself from the notion since the legislation was published, Gary Gray’s retort is correct. However, there might be scope to argue that the reforms will make an incremental contribution to informal voting in the House of Representatives, as voters might misread the message that they are no longer required to number every box.