Constitutional law – judicial power of the Commonwealth

High Court casenotes

In Garlett v Western Australia [2022] HCA 30 (7 September 2022), the High Court was required to determine whether the High Risk Serious Offenders Act 2020 (WA) (HRSO Act), insofar as its provisions apply to a person who has been convicted of a robbery, was contrary to Ch III of the Constitution by reason of the principle in Kable v Director of Public Prosecutions (NSW) (1996) 189 CLR 51.

In November 2017, Mr Garlett, in the company of others, broke into a home and, with threats of violence, stole a pendant necklace and $20 in cash. He was arrested the following day and pleaded guilty to offences of robbery and assault with intent to rob (November 2017 offences).

At the time of his arrest, Mr Garlett had a lengthy history of offending. Indeed, Mr Garlett committed the November 2017 offences a mere two months after being released from prison. Mr Garlett also had a record of poor behaviour while in custody.

Mr Garlett had abused alcohol and drugs from the age of 12. And Mr Garlett admitted that, at the time of the November 2017 offences, he had been injecting methylamphetamine daily.

On 29 July 2021, the State applied for a restriction order under the HRSO Act, in relation to Mr Garlett and based on the November 2017 offences. Section 35(1) of HRSO Act provides that the first respondent (State) may apply to the Supreme Court of Western Australia for a restriction order in relation to a “serious offender under a custodial sentence who is not a serious offender under restriction”.

A ‘serious offence’ is defined in s5(1) of the HRSO Act to be an offence specified in Schedule 1. Relevantly, Schedule 1 lists robbery and assault with intent to rob as serious offences. Under s48, the court must make either a continuing detention order or a supervision order if the court finds that the offender is a ‘high risk serious offender’.


Section 7(1) of the HRSO Act provides that an offender is a high risk serious offender if the court is “satisfied, by acceptable and cogent evidence and to a high degree of probability, that it is necessary to make a restriction order in relation to the offender to ensure adequate protection of the community against an unacceptable risk that the offender will commit a serious offence”. Section 7(2) sets out the range of matters the court must have regard to in making this determination.

In response to the State’s application, Mr Garlett challenged (among other things) the validity of the HRSO Act. Mr Garlett argued that the decision in Kable established that legislation which purports to confer, on a court, a function which substantially impairs the institutional integrity of the court – in its role as a repository of federal jurisdiction under the Constitution – is repugnant and incompatible with that role, and invalid.

The primary judge (Corboy J) held that the impugned parts of the HRSO Act did not confer powers on the court that were repugnant and incompatible with the court’s role as a repository of federal jurisdiction. The primary judge relied on the decision of Fardon v Attorney-General (Qld) (2004) 223 CLR 575, in which the High Court upheld the validity of the Dangerous Prisons (Sexual Offenders) Act 2003 (Qld) (DPSO Act).

Mr Garlett appealed to the Court of Appeal of the Supreme Court of Western Australia. Gordon J later ordered that this part of the appeal, which concerned the Kable ground, be removed to the High Court pursuant to s40 of the Judiciary Act 1903 (Cth).

Before the High Court, Mr Garlett relied on the statement of principle by Brennan, Deane and Dawson JJ in Chu Kheng Lim v Minister for Immigration, Local Government and Ethnic Affairs (1992) 176 CLR 1 at 27, that “putting to one side the exceptional cases … the involuntary detention of a citizen in custody by the State is penal or punitive in character and, under our system of government, exists only as an incident of the exclusively judicial function of adjudging and punishing criminal guilt” (the Lim principle).

But, a majority of the High Court (Gagler and Gordon JJ dissenting) were unpersuaded and upheld the primary judge’s decision.


Kiefel CJ, Keane and Steward JJ noted, at [4], the observations of Gleeson CJ in Fardon, at [20], that: “difficult questions involving the reconciliation of rights to liberty and concerns for the protection of the community … typically arise in the case of a small number of unfortunate individuals who suffer disorders which make them dangerous to others”.

Their Honours considered, at [69], that the HRSO Act was “materially indistinguishable” from the DPSO Act (as did Gleeson J at [291]), and held that the HRSO Act – like the DPSO Act – was directed to protecting the community from harm.

Citing Minister for Home Affairs v Benbrika (1992) 176 CLR 1 at 27-28 and 58, their Honours noted, at [48], that a State law will not be invalid merely because it provides for the detention of a person to protect the community from future harm, and that a determination about the risk of future harm is judicial in nature.

Their Honours seemed unimpressed, at [76]-[88], by Mr Garlett’s argument that the robbery was inherently insufficiently serious to be the basis for a restriction order. They observed, at [84], that whatever may be said about the inherent seriousness of robbery “in the abstract”, it is always for the court under the HRSO Act to determine whether there is an “unacceptable risk” the offender will commit the offence in the future (Edelman J makes the same observations at [278]-[282], as does Gleeson J at [313]).

Accordingly, their Honours concluded, at [107], the challenge to the validity of the HRSO Act fails, because the court – in making a restriction order – was required to act on its own evaluative judgment. Similarly, Gleeson J, at [314], concluded there was no aspect of the HRSO Act that compromised the independence or impartiality of the court. And Edelman J concluded, at [283], that considering the decisions in Fardon and Benbrika, the challenge to the validity of the HRSO Act must fail.

But Gageler and Gordon JJ (giving their reasons in separate judgments) allowed Mr Garlett’s appeal. Both Gageler and Gordon JJ declared that they did not think the offences of robbery and assault with intent to rob were of sufficient gravity to justify a restriction order (at [155] and [191], respectively).


Gageler J, at [159], considered that, if the Lim principle is still descriptive of our system of government, the HRSO Act – in respect of the offence of robbery – must contravene the restriction on State legislative power recognised in Kable.

Gordon J, at [200], complained that, with respect to robbery, the HRSO Act undermined the constitutional values that underpin Ch III of the Constitution by normalising preventative detention.

Dr Michelle Sharpe is a Victorian barrister practising in general commercial, real property, disciplinary and regulatory law, 03 9225 8722, email The full version of these judgments can be found at

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