The problems were due to the fact that the stridently-worded provision (“absolutely free”), intended at Federation to unify the colonies economically, seemed to bar even sensible regulation of interstate trade and movement.

For most of the 20th century, this resulted in s92 being, as Chief Justice Latham put it, a “boon to lawyers, road hauliers and to people who want to sell skins of protected animals or to trade in possibly diseased potatoes” across state lines. Both border-hopping and opportunistic litigation were rife as governments sought to regulate, plaintiffs tried their luck, and the High Court wrestled with how to interpret s92 in a way that was “absolutely free”, and the impact on legislation was not absolutely absurd.

There is a strong sense that the court had succeeded in laying s92 in 1988 with the decision in Cole v Whitfield, described by constitutional scholar Michael Coper as a “revolution” in s92 jurisprudence. This case concerned Tasmanian legislation banning the sale of undersized crayfish. South Australia, however, allowed catching smaller crayfish than Tasmania. Whitfield, a crayfish trader, was caught selling South Australian crayfish in Tasmania, which were undersized according to that state’s regulations. He claimed this was contrary to the freedom of trade and commerce protected by s92.

Reaching for their holy water, the High Court in Cole declared that, firstly, the “absolute freedom” of s92 was not, in fact, absolute and did allow for regulation. Moreover, what s92 meant was that trade and commerce should be free from “discriminatory burdens of the protectionist kind” — it was a guarantee of free trade among the states.

This was what the constitutional framers had meant by the words. While Cole clarified how s92 should be read in relation to trade/commerce, it did not rule on the intercourse limb.

And so, to 2020, when “creatures crawl in search of blood/to terrorise your neighbourhood” with disease and s92 lurched back into the light. The case was brought by Clive Palmer, a billionaire mining magnate and enthusiastic litigant.

The West Australian government had issued regulations under the Emergency Management Act 2005 (WA) that, from 5 April 2020, closed the state border to interstate travellers to prevent the spread of COVID-19. Mr Palmer, who lives in Queensland, wanted to enter Western Australia so that (as his United Australia Party said) he might visit his “full floor office in Perth’s Exchange Plaza, [his] home in Perth, and [use his] membership of the South Perth Yacht Club”. His application to be considered an “exempt traveller” allowed to enter the state was refused.

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Mr Palmer contended that the West Australian government’s border closure regulations were contrary to the protections of both the trade/commerce and intercourse limbs of s92. So, with the sense of déjà vu that one feels watching Halloween IX: Halloween Ends, the High Court turned again to the cursed section.

Startlingly, given the strong textual tradition in Australian jurisprudence since the Engineers case of 1920, the court explained that this section “was not to be taken literally”. The court went on to explain that the freedom of trade/commerce meant what they said it meant in Cole: freedom from “discriminatory burdens of a protectionist kind”. The border closure, although discriminatory, was not protectionist: it was for public health reasons, so it had not infringed s92.

However, the court also had to rule on the challenge to the freedom of intercourse limb, which Cole had not interpreted. Protectionism doesn’t make much sense when speaking of movement or communication, but the court held, the same “test of discrimination” between states was still apposite.

The freedom of interstate movement protected by s92, the court stated, meant deciding whether the burdens on interstate movement were discriminatory. Clearly here, yes — the regulations discriminated against non-West Australians.

For the last step in their reasoning, a majority of the court reached for another useful — but controversial — tool: structured proportionality. Using this interpretive tool, the court reasoned that although interstate movement was burdened, it was for a legitimate purpose, the means were suitable and necessary, and the balance between burden and benefit was acceptable. Mr Palmer paid costs. And the states cackled maniacally. (I’m sure I’m not just imagining that.)

Has Mr Palmer finally driven a stake through the heart of s92, settling its meaning and application? On the one hand, the court established definitively what exactly trade/commerce, and now also intercourse, should be free from. The irksome “absolutely” qualification has long turned to dust in the sunlight of regulation.

But, on the other, with structured proportionality, the court has provided itself with an interpretive tool that, as public law expert Thomas Poole described, “is plastic and can in principle be applied almost infinitely forcefully or infinitely cautiously”.

Structured proportionality’s native origins are in the explicitly, robustly developed human rights settings of Canada and Germany. It is arguable that in taking that super-flexible tool out of that systematic environment and bringing it to the marshy fog of s92, the court has given itself an overly wide discretionary scope. With extensive discretionary scope comes the potential for the make-up of the court to be very influential — and we’re back, Amityville-style, to reliving the pre-crayfish days.

Mr Palmer may have succeeded in nailing down the scrabbling corpse of s92. But with this constitutional “genre”, certainty requires another litigant to put it to the test. Palmer: The Sequel could well reveal that the court opened an interpretive hell mouth, launching another dark era of opportunistic litigation.