Premier of Tasmania Peter Gutwein (Image: AAP/James Gourley)

On Thursday, Tasmania joined other states in declaring a state of emergency over COVID-19. It also chose to take advantage of its unique geographical status, by essentially closing its borders to the rest of us.

Australia as a whole will have its drawbridge fully up from 9pm Friday, when the prohibition on non-residents from entering the country takes effect. We’re all prevented from leaving too. 

Tasmania has gone a step further: it is applying a 14-day mandatory self-quarantine period to everyone arriving on the island, including those coming from elsewhere in Australia. This is backed up by $16,800 fines for non-compliance. Everyone must fill out an arrival card.

In a social sense, fair enough. Who cares? Who the hell would be voluntarily getting on a plane right now, except to return home? Also Tasmania has been left off maps of Australia forever, so a bit of revenge is in order.

However, constitutional lawyers have been flipped into a frenzy by this move — not because it’s un-Australian but because it’s… no actually, it is because it’s un-Australian.

The problem is section 92 of the constitution, which says that “trade, commerce, and intercourse among the states, whether by means of internal carriage or ocean navigation, shall be absolutely free”.

I know what you’re thinking:

a) This isn’t trade or commerce, and why were the constitutional drafters worried about interstate sex?

b) A-ha, it doesn’t mention air travel.

c) Does “free” mean free of charge?

All wrong. The High Court is way ahead of you. 

Section 92 used to be one of the most hotly litigated provisions of the constitution, and the court resolved most of the technicalities a long time ago. “Intercourse” means the movement of people. Aeroplanes weren’t a thing in 1901, otherwise aviation would have been included, and the court has since implied it in on the basis that the wording wasn’t intended to be exclusive. And “free” means not prevented, impeded or made too hard.

The court’s understanding of why section 92 was included in our federation’s founding document is the obvious one: it was needed to ensure that Australia became a nation. The states had been essentially sovereign entities (albeit under British overlordship), with independently operated economies and systems of government. They were competitors for trade, and routinely imposed customs duties on each other’s goods as they crossed the border. To break that mindset and create an indivisible country would require the force of law, not just goodwill.

Naturally, lawyers and judges made an absolute feast of interpreting section 92 in practice, turning it into a constitutional law student’s nightmare. And finally, in 1988, the High Court came up with a more elegant explanation established in the case of Cole v Whitfield.

The court said that part of section 92’s purpose was to “deny to Commonwealth and states alike a power to prevent or obstruct the free movement of people, goods and communications across state boundaries”.

Pretty straightforward in theory, and easy to apply if a state government tried to stop another state’s produce at the border. But it’s not so simple in practice. Think of how you have to give up your NSW fruit when you cross into Victoria. In fact, there are heaps of interstate quarantine restrictions on various food and agricultural items.

The deal is that Victoria can get away with confiscating your fruit because its purpose in doing so is not to prevent NSW producers from competing in the Victorian market; it’s just trying to keep itself free of fruit flies. The same rationale underpins all the interstate quarantine laws.

So, to COVID-19. At first blush, the domestic quarantine rule is a clear contravention of section 92. In a very material way, it obstructs the free movement of people across state borders. In practical effect, it will stop it altogether. 

Tasmania is a physical and cultural paradise, but 14 days in a Hobart hotel room would kill anyone.

However, like the fruit fly, there’s more to the story. The Tasmanian law applies to everyone, including Tasmanians returning home, so it’s not directly discriminatory in its purpose or effect. More importantly, the reason it is being implemented is difficult to distinguish from the agricultural quarantine laws that have been held to be valid.

The Tasmanian government, understandably, wants to minimise the spread of COVID-19 among its population. So do the other states — but their land borders with each other are historical accidents, of no real physical relevance and completely permeable in practical terms. Closure of borders between essentially indivisible parts of the same country would divert resources for no useful outcome.  

Tasmania is different. It can effectively close itself off, with a material effect on the spread of infection. That’s why the government has elected to take that drastic step.

Legally, therefore, I tend towards the same conclusion that I reached from an ethical perspective. It’s deeply unfortunate that this should ever have had to be contemplated, but the purpose is to save lives and employ a geographical feature that happens to lend itself in that purpose’s favour. 

We haven’t batted an eyelid at the closure of remote Indigenous communities to keep them safe from COVID-19. I can’t see a relevant difference here.

To put it another way: if you were in charge of an island state far off the mainland coast, what would you do?