High Court Holds ACT Same Sex Marriage Law Is Inconsistent with Federal Marriage Law and of No Effect

Case Note by Eugenia Levine

The Commonwealth of Australia v The Australian Capital Territory [2013] HCA 55

In a unanimous judgment, six members of the High Court held in The Commonwealth of Australia v The Australian Capital Territory [1] that a new law of the Australian Capital Territory (the ACT) allowing for same sex marriage, the Marriage Equality (Same Sex) Act 2013 (ACT) (the ACT Act), was inconsistent with the Marriage Act 1961 (Cth) (the Federal Act) and, therefore, of no effect.

The High Court Decision

In addressing the question of whether the ACT Act was inconsistent with the Federal Act, the Court first turned to consider the scope of the “marriage” power conferred on the federal Parliament by s 51(xxi) of the Constitution.  If the federal Parliament did not have power to make a national law with respect to same sex marriage, the ACT Act would provide for a kind of union that federal Parliament could not legislate to establish and would then operate concurrently with the Federal Act.

The Court considered whether the s 51(xxi) power could be said to be limited to any well-settled meaning of the term “marriage” at the time of federation and firmly rejected this proposition.  The Court opined that s 51(xxi) gives the Parliament legislative power with respect to a status reflective of a social institution, and that the rights and obligations which attach to that status and social institution have never been immutable.  Accordingly, there is no basis to read the “marriage” power in the Constitution as tied to the state of the law with respect to marriage at federation.  Marriage law is not, the Court held, a matter of precise demarcation but, rather, “a recognised topic of juristic classification”.  On that basis, when used in s 51(xxi), “marriage” is a term which includes a union between persons of the same sex.

The Court next considered whether the ACT Act was inconsistent with the Federal Act.  Rather than invoking s 109 of the Constitution, the Court considered inconsistency under s 28 of the Australian Capital Territory (Self-Government) Act 1988 (Cth) (the Self-Government Law) on the basis that the ACT Act was enacted by a Territory.  Under s 28 of the Self-Government Law, a Territory law has no effect if it is ‘inconsistent’ with a federal law but “is taken to be consistent with such a law to the extent that it is capable of operating concurrently with that law.”

The Court observed that the Federal Act and the ACT Act cannot operate concurrently if, on its true construction, the Federal Act is to be read as providing the only form of marriage permitted shall be a marriage formed or recognised in accordance with that Act.  The Court concluded that the Federal Act does set the bounds of the legal status of “marriage” throughout Australia.  The provisions of the Federal Act (and, in particular, certain amendments introduced in 2004) make it plain that federal marriage law is an exhaustive statement of the law of marriage.  The provisions of the Federal Act contain “the implicit negative proposition that the kind of marriage provided for by the Act is the only kind of marriage that may be formed or recognised in Australia.”  Accordingly, the Court concluded that the provisions of the ACT Act providing for same sex marriage cannot operate concurrently with the Federal Act and are, therefore, inoperative.


The decision of the High Court makes a number of important pronouncements on the “marriage” power in s 51(xxi) of the Constitution and the ambit of the Federal Law regulating the legal status of marriage in Australia.  A significant aspect of the decision is the unanimous and unambiguous statement by the Court that the “marriage” head of power grants the federal Parliament legislative power to make a law providing for same sex marriage, confirming the existence of a clear legislative pathway for the creation of a uniform national same sex marriage entitlement.

[1]    [2013] HCA 55.

Eugenia Levine – CommBar profile

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