The Court has dismissed Day’s challenge, in effect rejecting all of his arguments.

In an important precedent, the Court rejected the claim that the new rules amounted to indirect voting, holding that a vote above the line was a direct vote for individual candidates consistent with the Constitution.

Day had also argued that optional preferencing was equivalent to disenfranchisement, since ballots which ran out of voter-marked preferences would stop influencing the result of the count. Again disagreeing, the Court held there was no disenfranchisement in the legal effect of the voting process.

The High Court has never previously upheld a specific challenge to a voting method design enacted by Parliament. The general thrust of constitutional law is that Parliament has a broad power to legislate on elections, and that Parliament is the proper forum for choosing the specific voting methods by which elections are held.

Updated post: The judgment in Day v AEC*

The Court handed down its full reasons for judgement in the Day case at the same time as announcing the ruling.

Firstly, in reviewing the previous legal precedents, the Court has affirmed a number of past one-judge decisions, the legal strength of which was arguably uncertain.

In particular, the original above-the-line voting system had been held to be valid by just the then Chief Justice Sir Harry Gibbs, sitting alone, in a hearing in McKenzie’s case in 1984. In recent months many commentators had speculated about whether Justice Gibbs’s sole opinion was a strong precedent. The Court has now clarified that it is.

On the specific merits of the current case, the Court has not been kind to the legal arguments presented by former Senator Day and his legal team.

In opening their response to Day’s complaints, the Court’s unanimous judgment gets going with the ominous statement:

“None of the above arguments has any merit and each can be dealt with briefly.”

The Court rather brutally dismisses the argument that the voting system passed by Parliament involves multiple methods, which Day claimed was not permitted. The Court replied:

“What the plaintiffs contended for is a pointlessly formal constraint on parliamentary power to legislate in respect of Senate elections which has nothing to do with the purpose of national uniformity.”

In the course of dealing with this argument the Court referred back to the 1897 constitutional convention debates over the drafting of the Constitution, quoting founding father (and second Prime Minister) Alfred Deakin as an authority that the drafters intended Parliament to have a wide discretion about what voting methods could be adopted, and whether they might have options for voters to use.

The Court clearly ruled today that ballot paper mechanisms that allow voters to ‘adopt’ rankings of blocks of candidates, as happens with the above-the-line system, are legitimate.

The Court did not go into any complex argument about any deeper definition of ‘direct’ voting, it simply characterised above–the-line voting as actually being a method of selecting individual candidates:

“The plaintiffs’ characterisation [of the nature of above-the-line voting] should not be accepted. A vote marked above the line is as much a direct vote for individual candidates as a vote below the line.”

Day’s argument that optional voting results in disenfranchisement fared no better – if anything it came off worse. The Court dismissed even the existence of the alleged principle of ‘direct proportionality’ that Day’s lawyers has asserted:

“There is no principle of “direct proportionality” to be infringed. There is no disenfranchisement in the legal effect of the voting process.”

The Court also bluntly rejected arguments that the form of the ballot paper, or the instructions to be written on it, were misleading.

This case has not fared well. The judgment is brief, and blunt, and displays a unified Court.

As to longer-term lessons about the constitutionality of specific voting devices, a few can be drawn.

The judgment confirms that ballot paper designs with above-the-line options, which are used for the Senate and in four Australian states, are valid. In effect it confirms that they (or at least, the methods hitherto used) are forms of direct voting for candidates, and that they have not impinged on voter choice.

The ruling has also in effect confirmed that optional preferencing does not amount to disenfranchisement. The Court fully heard the argument that where ballots ‘exhaust’ if they lack a full preference rankings of all candidates, the voters are disenfranchised – as Day claimed, that “3 million voters” would not have their votes counted – and comprehensively rejected the proposition.

What the judgment has not done is go further into the meaning of ‘direct’ election. It has not, for example, ruled on the possible use of European-style party list voting methods in Australia.

The Court stated that “The requirement of direct choice excludes indirect choice by an electoral college or some other intermediary.” But the Court did not clearly define what an ‘intermediary’ is, and in particular it did not comment on whether a political party is an intermediary in party list seat allocation electoral systems. The Court simply said: “That is not the case here.”

Without doubt, the case represents a broad affirmation of the Commonwealth Parliament’s power to choose voting systems.

Unless Parliament radically changes the voting system at some future point, the Day decision is likely to strongly discourage further litigation on the subject.

* Full citation: Day v Australian Electoral Officer for the State of South Australia and Madden v Australian Electoral Officer for the State of Tasmania, [2016] HCA 20, judgement handed down 13 May 2016