Parliament, the Executive and the Courts: Who Has the Last Word?
NSW Young Lawyers – Constitutional Law Address 2025
The Honourable Justice Geoffrey Kennett
3 November 2025, NSW Law Society

Introduction
When we discuss constitutional law, we are immersing ourselves in contemplation of the legal order that supplanted the laws of the first peoples of this continent. We should not lose sight of that, and the acknowledgement of country is therefore as important here as it is at any other gathering. Before I go further, therefore, I want to acknowledge the custodianship of this country of the Gadigal people over many millennia and pay my respects to their elders past and present.
My topic this evening concerns relations between the three branches of government. It is a topic of central importance to any constitutional order, but one that has received relatively limited attention in Australia. By and large it has not needed much attention, which is something for which we should be thankful. 
I was prompted to try to say something about this topic by recent and current events in another country. If you have not already guessed which other country I mean, it will soon become obvious. However, I will only touch fairly briefly and generally on those events towards the end of my address. That is partly because I do not have the depth of knowledge that would be needed to say something detailed, let alone original, and partly because the behaviour of the executive in that country is a topic of intense political controversy and therefore potentially dangerous territory for a sitting judge.
The “Washminster” System
I have assumed at the outset the existence of three branches of government – the legislature, the executive and the judiciary – because that is how our Commonwealth Constitution is structured. It is an arrangement that probably works as well as any but it is not divinely ordained. If one traces the antecedents of our legal system back into English history, it eventually becomes an anachronistic way of looking at things. Up until the time of the English Civil War, power was concentrated in the monarch to an extent that is surprising to modern eyes, including some legislative power and the power to interfere in resolution of disputes. It is only after the Bill of Rights of 1688 that one starts to see something like an independent judiciary and the concentration of legislative power in the Parliament. 
One aspect of that new constitutional order is parliamentary sovereignty – the notion that Acts of Parliament cannot be invalid. Another thing that needs to be kept in mind when considering the background to our constitutional order is that English institutions have adapted to the separation of powers gradually and not always completely.
I propose to say something about the power of the courts to pronounce on the validity of statutes and then something about judicial supervision of executive action. I will leave the relationship between the legislature and the executive to others.
In preparing for today I discovered that my colleague, Justice Perram, had addressed the topic of judicial review of legislation in his 2024 Maurice Byers Lecture. His Honour’s analysis of that topic is more detailed and scholarly than I can accomplish in the time available here, and I commend it to you. It can be found on the Federal Court website. Justice Perram made an interesting survey of the English constitutional history, which I am not going to attempt. I am essentially treating the creation of a written, federal constitution as a new beginning; but of course it was a new beginning that happened in a context.
That context included the experience of colonial government and the proud Britishness of the framers, but also – importantly here – the fascination exerted by the Constitution of the United States. Our system of government at the Commonwealth level has been called a “Washminster” system, because it blends a federal division of powers and a strong Senate, resembling the United States, with a system of responsible government in the British tradition.
Divided powers means that all governmental powers have limits and there will inevitably be controversies about whether those limits have been exceeded. Thus, as the prominent English constitutionalist AV Dicey wrote towards the end of the nineteenth century:
“Federalism … means legalism – the predominance of the judiciary in the constitution – the prevalence of a spirit of legality among the people”. 
It is hard to imagine a federal system without a written constitution forming its supreme law. That is what we have in this country.
Obviously, also, the three chapters of our Commonwealth Constitution reflect the three Articles of the US Constitution in establishing the three branches of government that I referred to earlier.
Marbury v Madison 
You have probably been waiting for me to say something about Marbury v Madison and I am going to do that now. That famous case concerned an application for mandamus against the executive, but its best-known passage is about statutes. It arose in a very turbulent time in the politics of the US, which reminds us that political turbulence is not really anything new.
To cut a very long story quite short, early in 1801, in the last days of the presidency of John Adams, a number of people were appointed as judges and justices of the peace for the District of Columbia. One of these was Thomas Marbury. The presidential election the previous year had produced an electoral college in which nobody could get a majority and the new President therefore had to be chosen by the House of Representatives. It seems that the outcome, which was the election of Thomas Jefferson as President, was not expected by the outgoing administration and it had been slow in delivering the commissions of appointment to the new judicial officers.  At any rate, when the new administration took office some of the commissions, including Marbury’s, had not been delivered. The new administration did not want these people and had no intention of delivering them their commissions. Late in 1801 Marbury applied to the Supreme Court for a writ of mandamus against the Secretary of State, James Madison.
The Jefferson administration managed to prevent the case being heard until February 1803 and then did not appear at the hearing. That is one unusual feature of the case. Another unusual feature is that the Chief Justice, John Marshall, who delivered the opinion of the Court, had been the Secretary of State in the previous administration who issued Marbury’s commission. Possibly, if the government had appeared, it might have suggested that he should recuse himself.
The case went off on a jurisdictional point and its ratio decidendi is that the Supreme Court did not have original jurisdiction in a claim for mandamus against an officer of the United States. But before addressing that issue, Marshall addressed the substantive question whether Marbury was entitled to mandamus and answered it with a resounding “Yes”. So Marbury won a moral victory but the Court avoided making a coercive order against the executive government which it might have simply ignored. 
As to the jurisdictional issue, there was a provision in the Judiciary Act of 1786 purporting to give the Supreme Court power to issue mandamus. But there was also a provision in Article 3 of the Constitution defining the original jurisdiction of the Court and it did not include mandamus. Marshall CJ held that the statutory grant of jurisdiction was repugnant to the constitutional provision and the latter had to prevail. He said that the phraseology of the Constitution:
“…confirms and strengthens the principle, supposed to be essential to all written Constitutions, that a law repugnant to the Constitution is void, and that courts, as well as other departments, are bound by that instrument”.
On the way to reaching this conclusion Marshall CJ made his famous observation that:
“It is emphatically the province and duty of the Judicial Department to say what the law is. Those who apply the rule to particular cases must, of necessity, expound and interpret that rule.”
The Australian view
Marbury v Madison was described as “axiomatic” by Fullagar J in the Communist Party Case but does not appear to have been actually cited in any Australian decision before then. It is probably more accurate to say that the understanding one sees expressed in Marbury about the consequences of having a written constitution, with judicial power vested in the courts, has been instinctively adopted by Australian judges.
A mildly interesting Australian postscript to Marbury v Madison is that s 75(v) of the Constitution, which has no equivalent in the US, was inserted specifically to avoid the outcome of that case. Section 75(v) is a very important provision because it entrenches the jurisdiction of the High Court to hear cases in which the lawfulness of actions by officers of the Commonwealth is challenged.
Section 75(v) was devised by that great Tasmanian, Andrew Inglis Clark, and included in the early drafts of the Constitution. It was left out of the 1898 draft at the instigation of Edmund Barton and Isaac Isaacs (two of the leading lights of the federation movement), on the understanding that it was not needed. Isaacs expressed the understanding that the US Supreme Court exercised the power to grant mandamus despite there being no provision for it in the Constitution of that country, which was simply wrong. 
Inglis Clark was not present at the 1898 Convention, but when he learned what had happened he sent a telegram to Barton referring him to Marbury v Madison. Barton sheepishly replied:
“None of us here had read the case mentioned by you of Marbury v Madison or if seen it had been forgotten – it seems however to be a leading case”.
Section 75(v) was quickly restored to the draft. Speaking to the Drafting Committee, Barton referred to the holding in Marbury that Acts repugnant to the Constitution were void. According to the records this excited no comment.
Justice Perram suggested in his lecture, and I respectfully agree, that the most likely explanation for this lack of reaction is that the principle was news to nobody.
The framers of the Australian Constitution were colonial politicians who were accustomed to seeing Acts of the legislatures to which they belonged either vetoed by Imperial authorities or declared invalid for inconsistency with superior laws. None of them could have failed to be aware of the notorious career of Justice Boothby in South Australia who, before being removed from the Bench, declared a raft of local laws invalid for repugnancy with the laws of England and prompted the passage of the Colonial Laws Validity Act 1865 (Imp) – an Imperial Act dealing specifically with questions as to when colonial legislation would or would not be valid.
Writings by people who were deeply involved in the Conventions, such as Inglis Clark himself and Harrison Moore, show an understanding that legislation inconsistent with the Constitution’s provisions would be void and that it would be the job of courts to identify that voidness. Some of this material is set out in an interesting article by Matthew Stubbs published in the Federal Law Review in 2012. 
For example, Quick and Garran, in their magnificent Commentaries on the Australian Constitution (1901), reminded the reader that the Constitution was binding on every individual and every government agency and noted that the provisions of the Constitution might be transgressed. They continued:
“Every person under these circumstances has recourse to the appropriate courts to defend his own rights and to enforce the obligations of others; and thus, without any express provision, the courts of the States, and the federal courts, whenever they have jurisdiction over a case, have the duty of interpreting the Constitution so far as it affects the rights of the parties.”
One more recent commentator who has sought to question the power of the courts to strike down legislation is Dr James Thomson, who taught for a long time at the University of Western Australia and worked for the Attorney-General’s Department in that State. The topic of his doctoral thesis at Harvard, and an introductory chapter that he wrote for a publication of the Convention debates, was what he saw as the lack of any proper explanation of why the courts should have power to strike down the legislation of a democratic parliament. In Thomson’s eyes, there was no textual foundation for such a power and it was hard to reconcile with the coequal status of the three branches of government.
My reading suggests that Thomson is a lone voice, at least in the serious reaches of academic commentary, and the Australian case law betrays no doubt about the legitimacy of judicial review.
My own view, for what it is worth, is that it is a mistake to imagine courts wandering around striking down laws. Courts in our system only decide the cases that come before them and have to decide the rights of the parties in those cases according to law. If those rights depend on a statute, and there is an argument that the statute exceeds constitutional power, the court has no option but to decide that issue. The court’s conclusion is going to bind the parties, and form a precedent that other courts will follow. If we want to have a society governed by the rule of law, we have to put up with these things.
To propose that the court cannot decide a statute is invalid is to say something about the status of the statute – that it is unchallengeable – rather than the status of the court. But a statute whose validity is beyond question is at odds with the whole point of a written constitution that divides power.
Courts do therefore have a form of supremacy over the other branches of government, but it is a very constrained and qualified one. It is not the result of the courts having free reign to strike things down. It is a function of the supremacy of the Constitution and the duty of the courts to decide the cases that parties bring before them. 
The passage in Quick and Garran that I read out a moment ago captures the position well. That passage was part of the commentary on s 76(i), which, as I am sure you remember, identifies matters “arising under this Constitution or involving its interpretation” as an aspect of federal jurisdiction and thus part of the judicial power.
Two early Australian cases should be mentioned before I leave this topic.
Before the High Court had been established, an action for penalties for a breach of the Customs Act 1901 (Cth) came before the Supreme Court of Victoria in Kingston v Gadd. The defendant argued that the relevant provisions of the Customs Act were beyond power, to which the plaintiff responded that the Court had no power to hold an Act of the Parliament invalid. The Full Court held that the provisions were valid but rejected the argument that that question was out of bounds.
Williams J referred to covering clause 5 and reasoned that, if laws made by the Parliament had not been made under the Constitution, they were not binding on the court; so that the court had a duty to inquire whether the provisions relied on were laws that the Parliament had power to enact. Holroyd and Hood JJ were to similar effect.
The Privy Council somehow managed to reach the contrary conclusion in Webb v Outtrim, which concerned the validity of a State Act. It was part of a controversy that pervaded the early years of federation over whether the States could impose tax on the salaries of Commonwealth officers. A dispute between the Commonwealth Deputy Postmaster-General and the Victorian tax authorities went on appeal from the Victorian Supreme Court to the Judicial Committee of the Privy Council. The Committee’s advice, which was delivered by Lord Halsbury, was that a State statute would be invalid if it were inconsistent with an Imperial Act but otherwise the Victorian Act was “an Act of Parliament as much as any Imperial Act”; there was no authority by which its validity could be impeached. His Lordship rejected any analogy with the United States. The judgment reads, with respect, as if his Lordship had simply overlooked the Commonwealth Constitution.
Webb v Outtrim does not appear ever to have been followed in Australia. The High Court held a Commonwealth statute invalid eleven days later in the Railway Servants case and has never stopped doing so. And the Privy Council was thereafter practically excluded from the business of Australian constitutional law, but that is another story.
Judicial review of executive acts 
Now I want to turn to judicial review of acts of the executive. 
At the level of principle this is rather less interesting than judicial review of legislation. The writs of prohibition and mandamus which are mentioned in s 75(v), and which around the turn of the millennium we started to refer to as the constitutional writs, are ancient remedies. So too are the injunction, also mentioned in s 75(v), and the writs of certiorari and habeas corpus which are not. When I was a student these used to be referred to as the prerogative writs, reflecting that in their deeper history these writs issued out of what were called the Royal Courts of Justice (and before that the King’s Privy Council) and the function of controlling public officers was seen as a prerogative function. This is an example of English institutions adapting gradually into forms consistent with the separation of powers.
The monarchical origins of the ancient writs led to a view that they would not go against the sovereign or the Crown per se. This was allied to the principle sometimes expressed as “the King can do no wrong”. The Australian Constitution upended these notions, although in some respects it took a while for this to be understood. It was not until Mewett v Commonwealth that a High Court majority regarded the liability of the Commonwealth in tort as flowing from the common law, as applied through the judicial power of the Commonwealth established by the Constitution, rather than the statutory grant of a right to proceed. 
The Crown’s former immunity from being subjected to writs issued out of its own courts is also rapidly fading from view in Australia if it has not already gone. Aronson, Groves and Weeks in their book Judicial Review of Administrative Action  list a series of cases in which the High Court has in effect not seen or wanted to talk about any “Crown”; only States, the Commonwealth, executive governments and their agencies and officers. All, one might note, entities owing their existence one way or another to the Commonwealth Constitution and therefore subject to the supervision of Australian courts. Decisions nominally made by vice-regal officers (in practice made on ministerial advice) have been acknowledged to be subject to judicial review since the 1980s.
If the writs are imagined as issuing under Royal authority to control holders of public offices, it is reasonably obvious why there should be no issue (at least in principle) about those public officers complying with them. But the establishment of a constitutional order in which authority flows from a written basic law, through institutions created by that law, confirms what must already have become the reality in practice by the time of federation: that it is the courts, by the authority they possess, telling public officers what they can and cannot do.
A common feature of the exercise of judicial power is that it brings the coercive power of the state to bear against the unsuccessful party. But this becomes complicated if the unsuccessful party is the state itself, in the form of the executive, or an officer who has the support of the executive. Put shortly, the courts do not have the physical resources to coerce the executive.
In this country and in the UK it is common, in cases involving the executive, not to grant coercive orders such as an injunction or mandamus unless some specific need to do so is established. This reflects an assumption that the executive believes in the rule of law and will usually comply with the law as the court declares it. In a judgment delivered in 2022, Craig v HM Advocate, the UK Supreme Court said this.
“The Government’s compliance with court orders, including declaratory orders, is one of the core principles of our constitution, and is vital to the mutual trust which underpins the relationship between the Government and the courts. The courts’ willingness to forbear from making coercive orders against the Government, and to make declaratory orders instead, reflects that trust. But trust depends on the Government’s compliance with declaratory orders in the absence of coercion. In other words, it is because ours is a society governed by the rule of law, where the Government can be trusted to comply with court orders without having to be coerced, that declaratory orders can provide an effective remedy.”
I have not found an Australian case in which a Commonwealth officer or authority has refused to comply with an order of a Court.
A slightly different position pertains to the reasoning of superior courts on points of statutory construction. If a court pronounces on the meaning of a statutory provision, that becomes res judicata only between the parties to the case, but a strong expectation arises that officials will administer the statute consistently with the court’s interpretation. In Commissioner of Taxation v Indooroopilly Children Services, Allsop J gave a stern lecture to the Australian Taxation Office, which appeared to be administering the relevant legislation on the footing that several single judge decisions were wrong and would eventually be corrected on appeal. This is not a flouting of court orders but it is a challenge to the usual relationship between the government and the courts and is likely to attract adverse comment. It is conduct that is “unlawful”, in the sense of being contrary to the law as authoritatively expounded by a court at the time. 
Such conduct can perhaps be justified in some circumstances, for example as a method of creating a test case, but it usually provokes strong disapproval.
Defiance of actual orders has recently become a real prospect in the United States, which is what prompted me to choose this topic (and what I have so far avoided talking about).
It is fairly notorious that the second Trump administration has a particular view about the scope of presidential power and has chafed against court orders restraining the implementation of some of its policies. It has not (so far as I am aware) reached the stage of Justice Department lawyers expressly rejecting the legitimacy of a court’s orders or conveying a direct refusal to comply, but it has come close. What has occurred in the last few months includes:
•	executive agencies ignoring temporary injunctions directing the government not to carry out policies such as a federal funding freeze or prohibiting diversity, equity and inclusion (DEI) programs; 
•	continuing to withhold foreign aid funding despite an order to at least temporarily restore that funding; 
•	failing to “turn around” flights of immigrants removed (purportedly) under the Alien Enemies Act of 1798, and destined to be imprisoned in extremely harsh conditions in El Salvador; 
•	overt outrage expressed by the executive over injunctions preventing them from expanding access to federal payment systems; and
•	taking steps to impeach judges who have ordered injunctions against the Government. 
The Washington Post reported in July 2025 that the President and his appointees were accused of flouting court orders in a third of cases out of a sample of more than 160 lawsuits.
Summary and observations
There are just a couple of observations that I want to make about this.
One is that there now seems to be an emerging genre of academic writing in the US looking at the options available to the courts and the calculations that the courts might make in deciding how to respond to defiance of their orders. The fact that people are having these conversations indicates that damage is already being done to the constitutional order. 
The position of the US Marshals, who are charged with enforcing orders, is complicated, and there are a range of remedial steps (also complicated) that might be taken against particular officers or in particular cases. But the bottom line is that courts do not have the physical capability of enforcing their orders if the executive branch is resolute and united in resisting them. And the prospect of armed confrontation between Marshals (or the citizenry) trying to enforce orders and a lawless executive resisting them is probably not one that judges want to contemplate.
The other thing that is interesting, and not in a good way, is that some of the commentary I have read and heard recently expressly contemplates that the courts might already be tailoring their decisions in order to avoid a confrontation with the executive. One thing that enables this kind of speculation to occur is that some decisions of practical significance have been made by the Supreme Court in its so-called “shadow docket”, where no reasons are given. We thus see the beginnings of a loss of confidence in the courts themselves as institutions.
This is a depressing note on which to end. 
I do not suggest that what I have just described is likely to happen in this country. The political and legal cultures are very different. However, it gives us cause to reflect on the importance of respect between the branches of government and the value of what Dicey referred to as “a spirit of legality among the people”.