The High Court has upheld a state law that undermines a core guarantee of liberty and will disproportionately punish Indigenous offenders. By Kieran Pender.

The High Court’s disturbing ruling on preventive detention

Western Australia’s attorney-general, John Quigley.
Western Australia’s attorney-general, John Quigley.
Credit: AAP Image / Dean Lewins

If it were not for the passage of a new law – last week found to be constitutional by the High Court – Peter Garlett and Derek Ryan would be free men. In 2017, Garlett, a Noongar man from Western Australia, broke into a house pretending to be armed with a handgun, stealing a pendant necklace and $20. He pleaded guilty and was given a custodial sentence of three years and six months. Ryan, another Noongar man, served 12 years, also for robbery offences.

It is, or perhaps was, a fundamental Australian legal principle that the involuntary detention of citizens is punitive in nature and can take place only as part of the judicially overseen criminal justice process. Once a custodial sentence has been served, the prisoners must be released. This principle, known in Australia as the Lim rule, goes to the heart of our system of government, the separation of powers and the rule of law. It is a core guarantee of liberty.

But as a consequence of the High Risk Serious Offenders Act, enacted by the Western Australian parliament in 2020, Garlett and Ryan were not free men. Garlett was kept behind bars for over six months following the end of his sentence, after a judge determined that there were “reasonable grounds for believing” he might reoffend if released. Ryan was released but subjected to a curfew and other limitations.

Last year, Garlett challenged the constitutional validity of the HRSO Act, with Ryan joining as an amicus curiae, or friend of the court. They argued that the ongoing restrictions on their liberties occasioned by the act were contrary to chapter III of the constitution, offending the Lim principle. 

This month, they lost – with five judges of the High Court holding that the law was constitutional.


The HRSO Act represents a stark departure from fundamental legal principles. It does this in the name of preventive justice – supposedly keeping the community safe from future criminal offending. In a statement following the High Court’s decision, WA Attorney-General John Quigley, the law’s architect, said: “Western Australians have the right to feel safe in their communities and these laws enable courts to keep the most dangerous criminals behind bars, in line with the community’s expectations.”

But the law, and the High Court’s judgement, have drawn criticism. “Labelling the HRSO Act scheme, and the role of the Supreme Court, as ‘preventive justice’ is a misnomer,” wrote Justice Michelle Gordon in a dissent. “It is not justice.” 

Justice Stephen Gageler joined Gordon in opposing the law. The WA Justice Association, a law student group led by an ex-prisoner, was even more damning. “The HRSO Act must be called out for what it is: racist legislation,” they said in a statement. 

“First Nations Australians are grossly over-represented in WA prisons and will, in turn, be disproportionately subject to continuing detention orders under the HRSO Act. The HRSO Act will worsen the over-representation of First Nations people in WA prisons, not improve it,” they said. 

Aboriginal people already comprise about 40 per cent of the adult prison population in WA, despite constituting about 4 per cent of the general population.


The Australian constitution, by granting legislative power to the federal parliament, executive power to the government and judicial power to the courts, erects a strict separation of powers. Citizens can only be imprisoned by the courts, as this is punitive, and punishment is an exercise of judicial power, a consequence of the separation of powers, as recognised in Chu Kheng Lim v Minister for Immigration, Local Government and Ethnic Affairs. Other than by judicial order, the court held in this 1992 immigration detention case, “the citizens of this country enjoy ... constitutional immunity from being imprisoned”.

But in Lim the High Court offered a caveat. Non-judicial detention could be permissible in “exceptional cases” – such as to deal with mental illness or infectious disease – where the purpose of detention can “legitimately be seen as non-punitive in character”. Hence no constitutional challenge was ever brought to the Covid hotel quarantine scheme, which was directed at public health purposes, not punishment.

Lim concerned federal power. State constitutions do not mandate a strict separation of powers. However, because the Australian constitution permits the federal government to grant jurisdiction to state courts, the High Court has held that state parliaments cannot give state courts powers that undermine their institutional integrity. This was the basis upon which Garlett and Ryan brought their challenge to the HRSO Act.

This latter principle arose in the case of Kable v Director of Public Prosecutions (NSW), in 1996. Gregory Kable had served a sentence for the manslaughter of his wife. With his release date nearing, the New South Wales parliament passed a law empowering the state’s Supreme Court to issue a preventative detention order. Although the law stated its purpose was “to protect the community”, it singled Kable out by name. The High Court did not like this – and invalidated it on the basis that it impaired the Supreme Court’s institutional integrity.

Despite the outcome, Kable did not quell legislative enthusiasm for so-called preventative detention powers. Eight years later, a Kable challenge was brought to a Queensland law empowering its Supreme Court to issue continuing detention orders where sex offenders were considered a risk to the community. In that case, Fardon v Attorney-General (Qld), a majority of the High Court upheld the law, on the basis that it fell within the exception to Lim. This was because the law was directed at protecting the community, not punishing the individual. In Minister for Home Affairs v Benbrika, a case decided last year, the High Court upheld a similar ongoing detention regime under a federal law directed at those convicted of terrorism offences.

These cases divided the judges and elicited considerable academic criticism. But they involved sex offenders and terrorists. The question in Garlett was whether the same reasoning could justify the ongoing detention of someone convicted of robbery – Garlett’s conviction was his first as an adult, though he had a history of youth offending. Last week, a majority of the High Court said it could.


In the lead judgement, Chief Justice Susan Kiefel and justices Patrick Keane and Simon Steward described Garlett as an “unfortunate” individual. Pointing to his “history of offending” and drug and alcohol abuse, they rejected his lawyers’ arguments that robbery could never be a sufficiently serious offence, giving rise to such risk to the community as to justify an exception to the Lim principle.

“This aspect of Mr Garlett’s argument culminated in a plea that this Court strike down the HRSO Act lest the legislature be emboldened to designate a failure to wear a helmet while riding a bicycle as a ‘serious offence’ for the purposes of the HRSO Act,” the judges held. “This kind of rhetorical device provides no substantial basis for regarding robbery as something other than a serious offence.” Otherwise, they said that the WA law was “materially indistinguishable” to the Queensland law upheld in Fardon, and hence the challenge could not succeed.

In reaching this conclusion, the judges showed considerable deference to the WA parliament’s decisions. “The inclusion of an offence, such as robbery [in the HRSO Act] reflects a legislative judgment as to the kinds of offences which may be such as to cause harm of a kind from which the community needs protection different from that provided by the criminal law,” they observed. “It is not inimical to the institutional integrity of the Court to act upon [such] legislative judgment.”

In thundering dissents, justices Gageler and Gordon said it was indeed possible to distinguish between terrorism and sex offences as truly exceptional, and robbery as not. Gageler pointed to the “contemporary trend towards expansion in the range of offences legislatively designated to be sufficiently ‘serious’ to justify preventive detention.” 

To allow this to continue, he held, “would be to permit the Lim exception to hollow out the Lim norm.”

Justice James Edelman, writing separately, upheld the law in its narrow application to the case before the court, yet made a number of pointed comments – including about the law’s potentially discriminatory impact on Indigenous Australians – that suggested he might reach a different conclusion in the future. 

“But an assessment of the impact of such practical effects upon the validity of continuing detention orders,” he wrote, “must await a case which raises those legislative facts.” Justice Jacqueline Gleeson, the newest judge on the bench, also upheld the law.


“We were prepared for the worst,” Dr Hannah McGlade, a Noongar woman, lawyer and associate professor at Curtin University, who was part of Garlett’s legal team, tells The Saturday Paper. 

“Aboriginal people don’t often see justice in our courts. So it wasn’t unforeseen, but it was still shocking. It’s a repetitive pattern where Aboriginal people cannot get the benefit of the rule of law or legal justice in our courts, even in a case with significant merit.

“This changes the nature of the justice system as we know it,” McGlade continues. “It has always been a principle of our legal system that a person, if found guilty, is convicted and sentenced for their crime. Most recently we have the courts acting at the behest of parliament to arbitrarily detain people based on some fancy guesswork and risk-assessment tools that have never been validated, were never designed for punitive measures, and are prone to racial bias and prejudice.”

One senior barrister not involved in the case points to the absence of liberty-protecting clauses in the Australian constitution, in distinct contrast to other constitutions such as in the United States. While prior High Court judges have reached for structural implications, as in Lim, to provide some protection, that approach may have reached its limit. “One problem with our constitutional law is that, even though it’s not designed to protect rights, a decision not to invalidate laws like this is regarded as the High Court ‘approving’ them,” they say.

But without such express rights, and in light of the trend in recent case law, the senior counsel suggests that the outcome in Garlett seemed inevitable. “I kind of feel like we are heading down a slope in [recent cases], and now there’s no clear or convincing branch to grab onto to stop the slide,” they add.

In light of Fardon, Benbrika and now Garlett, there are few constitutional limits on preventative detention regimes. What was once, even just two decades ago, a truly extraordinary and constitutionally dubious departure from traditional criminal law has become a normalised law-and-order policy approach, with the High Court’s blessing.

“The potential expansion of preventive detention to address all manner and kinds of criminal offending is by no means far-fetched – it is not an extreme or distorting possibility,” wrote justice Gordon in her dissent. Instead, with the HRSO Act and other increasingly common laws, “the judiciary is left to perform the executive function of preventing a wide range of crimes one offender at a time”.


Garlett, now 28, has been released from his post-sentence detention. But he remains subject to a “supervision order” – as does Ryan. Garlett’s lawyers, Roe Legal, have said they are contemplating a complaint to the United Nations. But even a UN finding that the law is contrary to Australia’s international human rights obligations would not render it invalid.

With the High Court having upheld the HRSO Act, Garlett and Ryan will – in the months and years ahead – be joined by more ex-prisoners subject to continued detention or post-detention restrictions, which can include 24/7 monitoring and travel bans. That group will be disproportionately Aboriginal. 

“I am devastated by the decision,” Ryan said in a statement through his lawyers, the National Justice Project. “I was relying on justice and common sense – this decision is unjust.”

This article was first published in the print edition of The Saturday Paper on September 17, 2022 as "Justice withheld".

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