The Nauruan government announced earlier this week that it will remove the remaining restrictions on the liberty of the asylum seekers detained there, and process all pending claims for asylum. It initially said it would process the claims in a week, but has since backtracked from that commitment.

Many have claimed that the announcement is a strategic move to undermine a constitutional challenge to Australia’s offshore detention regime, heard by the High Court this week – although the Australian government has denied this. So does the policy change spell the end of the challenge?

While that question can only be answered after the High Court’s decision, the hearings give a hint. The short answer is that the Nauruan government’s announcements have already had a much greater effect in the High Court than on Nauru itself.

So what is this case about anyway?

The plaintiff in this case is a Bangladeshi woman who was detained on Nauru before being brought to Australia during her pregnancy. If the case fails, she, her ten-month-old baby and more than 200 people now in Australia will be sent back to Nauru or Manus Island.

The case, together with a similar one relating to Manus Island, began as a challenge to the Commonwealth’s power to spend money on offshore processing centres. This was on the basis of recent High Court cases that found that legislation was generally required to authorise the Commonwealth entering into contracts and spending money, subject to certain exceptions.

Not unusually, parliament intervened. In late June, the major parties combined to pass “emergency” authorising legislation, which applied retrospectively.

This meant the plaintiff was forced instead to argue that the emergency legislation was invalid because it did not fall within the Commonwealth’s powers to make laws set out under the Constitution. As the High Court’s questions made clear, this is a difficult argument to run. The authorising legislation appears clearly related to at least two of the broadest legislative powers of the Commonwealth – the power to regulate aliens and the power to engage in external affairs.

The plaintiff’s main argument now was that the Commonwealth, by in effect detaining asylum seekers on Nauru, went beyond its constitutional power to detain. The argument rested on two main steps.

First, previous cases had established certain constitutional limits on the executive’s power to detain asylum seekers in Australia. These limits included that such detention must be limited to permissible purposes and limited in time to what was reasonably practicable to effect that purpose, and that the courts must be capable of supervising the legality of that detention.

Second, these constitutional limits did not apply to detention on Nauru. The effect of this was that the offshore processing regime enabled Australia to do outside its borders what it could not do inside. This would in effect subvert the High Court’s role in supervising the constitutionality of executive power.

At the heart of this was an argument that the Commonwealth was to be treated as, in substance, detaining the asylum seekers. That argument rested on the evidence that the Commonwealth funded, authorised and controlled the offshore processing regime.

This is a difficult argument to run. Similar arguments failed last year before the High Court. As High Court justices pointed out this week, there is nothing in either the Migration Act or the Memorandum of Understanding that requires Nauru to detain asylum seekers.

How did Nauru’s announcement change the case?

Nauru’s announcements over the past week significantly undermined the plaintiff’s main argument. This argument rests on there being unconstitutional detention, and now there is no detention.

As a consequence, the Commonwealth argued that all of the questions (and associated remedies) in the case relating to the Commonwealth’s future conduct were no longer relevant.

The Commonwealth is also now arguing that it is not useful for the High Court to consider the legality of past detention. This is because deciding that question will not produce any real consequence for the plaintiff.

That might surprise lay observers, but Australian courts have long held that the courts should not decide cases where it can serve no useful result. While a claim for compensation could have been such a result, the case was never argued in this way – as the Commonwealth duly pointed out.

Circumventing the courts

From this week’s hearings, it certainly seems that these sudden changes to policy in Nauru have dramatically weakened this constitutional challenge – if not yet the companion challenge to the constitutionality of offshore processing on Manus Island.

Yet again, it seems, the government may have successfully outmanoeuvred legal challenges by changing the law and the facts on the ground.

For the asylum seekers on Nauru, other facts on the ground remain much the same. They are still unsafe, separated from their families and unable to leave Nauru for a real life.