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Common(wealth) Knowledge #3: Judicial Review, Marriage Equality & the Constitution

Updated: Apr 7, 2023

A look at courts in Australia's states and territories.

On 14 July, the Victorian Court of Appeal ruled that mandatory minimum sentences imposed by legislation were unjust; however, because statutory law has supremacy over common law, the Court of Appeal was forced to give an 18-year-old a three-year mandatory sentence. See 6 News’ coverage of that case, Buckley v The Queen [2022], here. However, it raises the question of whether courts can ever overrule legislation.

The ‘rule of law’ is a set of principles that govern democratic countries. One of the most important principles is the separation of powers, which requires the judiciary, legislature, and executive to be separate from one another. See here for how this separation of powers operates in Australia. The separation of powers requires each branch of government to limit the others, and keep them accountable, through what is known as ‘checks and balances.’ In the case of the judiciary, this power is unimaginatively called ‘judicial review.’

Section 76(i) of the Australian Constitution allows the Commonwealth Parliament to grant the High Court of Australia jurisdiction over all matters involving the Constitution, known as constitutional law. Parliament did this in Section 30(a) of the Judiciary Act 1903 (Cth). In addition, Section 75(v) of the Constitution allows the High Court to hear court cases involving the executive branch of the government, when the executive has been accused of breaking the law. Section 76(i) allows the High Court to hear Section 75(v) cases that involve a breach of the Constitution. Under Section 76(i), the High Court can also hear cases about Parliament breaching the Constitution.

Possibly the most famous part of constitutional law is Section 109 of the Constitution. Section 109 states if a Commonwealth law and a State (or Territory) law are inconsistent, the State law “shall, to the extent of the inconsistency, be invalid.” This is important in a federal system. If both levels of government can pass laws on the same subjects, the Commonwealth law will triumph. This means that if the Commonwealth Parliament had passed a law to ban mandatory minimum sentences, that could be used to prevent the Victorian government from passing these ‘unjust’ laws.

However, like many things in law, it is not that simple. The same federal system that allows Commonwealth law to triumph also limits the situations in which it can triumph. The Commonwealth Parliament can only pass laws on subjects, or ‘heads of power,’ that it is authorised to by the Constitution. It has ‘exhaustive powers,’ because it is possible to write a list of all subjects that it can pass laws on. In contrast, State Parliaments have ‘plenary powers,’ because an exhaustive list cannot be written.

There are only a few areas where States can’t legislate at all. But there are many areas where both levels of government can pass laws, especially the subject areas found in Section 51 of the Constitution. If there is no constitutional head of power that allows Parliament to pass laws on a subject area, Section 109 is not relevant. There is no head of power relevant to mandatory minimum sentences. But if there was, this would be where Section 109 comes into play.

A recent, controversial use of this power was in the Same Sex Marriage Case (2013). In this case, the Australian Capital Territory tried to legalise same-sex marriage, by defining ‘marriage’ in the Marriage Equality (Same Sex) Act 2013 (ACT) as “the union of 2 people of the same sex to the exclusion of all others, voluntarily entered into for life.” In contrast, the Marriage Act 1961 (Cth) used the phrase “the union of a man and woman.” The Commonwealth government immediately reacted to this by taking the matter before the High Court, where it was found that the ACT Act was invalid, because Section 51(xxi) of the Constitution grants the Commonwealth Parliament the authority to legislate on marriage. Because the two laws, both of which passed their respective legislatures legally, were inconsistent, the Commonwealth won. It’s worth noting that Section 109 applies to States, not Territories, but Section 28 of the Australian Capital Territory (Self-Government) Act 1988 has the same effect.

4 years later, the Australian public told the Commonwealth government that they believed same-sex marriage should be legal. Section 109 is not concerned with whether a law is moral, only whether it is legal. It doesn’t matter that the residents of the ACT supported same-sex marriage, or that it was passed by their democratically-elected legislature; it wasn’t constitutional, so it was invalid.

Courts in the States and Territories, such as the Victorian Court of Appeal, do not have similar powers, when it comes to inconsistency between constitutions and legislation. If a similar federal system existed at that level, with States and Territories sharing legislative authority with local government areas, there may be a need for this. Similarly, if States and Territories had their own constitutional bills of rights, this power of judicial review might exist.

Judicial review is not concerned with the morality or ‘correctness’ of laws, only with their legality. When it comes to the executive branch of government, alternatives to judicial review have been developed, like ‘merits review,’ which is more focused on whether an action is just. However, similar developments have not been made to judicial review of the legislature, only giving the judicial system limited authority to overrule legislation, and even then, the authority to overrule legislation must come from the Constitution, which has more authority than legislation.

Stuart Jeffery is a freelance researcher & digital editor for 6 News. His views on personal social media pages are his & his only, and do not reflect the views of 6 News or our journalists. He abides by 6 News' editorial standards relating to fairness & accuracy.

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Australian Capital Territory (Self-Government) Act 1977 (Cth).

Buckley v The Queen [2022] VSCA 138.

Commonwealth of Australia Constitution Act 1901 (Imp), 63 & 64 Vict, c 12.

Commonwealth v Australian Capital Territory (2013) 250 CLR 441; [2013] HCA 55.

Judiciary Act 1903 (Cth).

Marriage Act 1961 (Cth).

Marriage Equality (Same Sex) Act 2013 (ACT).


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