The High Court decision on marriage equality legislation

In Commonwealth v Australian Capital Territory (12 December 2013), the High Court of Australia (HCA) held unanimously that the Marriage Equality (Same Sex) Act 2013 No 39 (ACT) was invalid, since it could not operate concurrently with the Marriage Act 1961 (Cth) (Marriage Act).

The Australian Capital Territories (ACT) legislation had provided for same sex marriage. The HCA held that the Marriage Act, which defined marriage being as between persons of the opposite sex, was a comprehensive and exhaustive statement of the law with respect to the creation and recognition of the legal status of marriages in Australia.

Lawyers and commentators are now studying how this decision will affect the future of same-sex marriage laws, and the meaning of the word “marriage” in s 51(xxi) of the Constitution, which gives the federal Parliament power to make laws with respect to “marriage”.

The traditional definition of marriage defines it as a relationship between a man and a woman. In the year 1866, an English court stated “marriage, as understood in Christendom, may for this purpose be defined as the voluntary union for life of one man and one woman, to the exclusion of all others”. It has been since argued that the word “marriage” has the same meaning in our Constitution.

The HCA decisively held, however, that the word “marriage” does not have this narrow meaning in the Constitution. The HCA judgment stated:

Because the status, the rights and obligations which attach to the status and the social institution reflected in the status are not, and never have been, immutable, there is no warrant for reading the legislative power given by s 51(xxi) as tied to the state of the law with respect to marriage at federation…

The question remains that if “marriage” as used in the Constitution does not have the same meaning of the word as it was used in the 19th-century English case law, then what does it mean? Could the word “marriage” include, for example, two persons sharing a flat, or even multi-partner arrangements?

The HCA did not provide a list of relationships that might possibly be described as “marriage”.  It merely said that the topic of marriage was “not a matter of precise demarcation”.

The HCA did note, however, that “marriage” could include polygamous marriages.

The court does make a decisive judgement that the word “marriage” can include same-sex unions.

The full text of these relevant passages in the decision follow:

The social institution of marriage differs from country to country. It is not now possible (if it ever was) to confine attention to jurisdictions whose law of marriage provides only for unions between a man and a woman to the exclusion of all others, voluntarily entered into for life. Marriage law is and must be recognised now to be more complex. Some jurisdictions outside Australia permit polygamy. Some jurisdictions outside Australia, in a variety of constitutional settings, now permit marriage between same sex couples.

These facts cannot be ignored or hidden. It is not now possible (if it ever was) to decide what the juristic concept of marriage includes by confining attention to the marriage law of only those countries which provide for forms of marriage which accord with a preconceived notion of what marriage “should” be. More particularly, the nineteenth century use of terms of approval, like “marriages throughout Christendom” or marriages according to the law of “Christian states”, or terms of disapproval, like “marriages among infidel nations”, served only to obscure circularity of reasoning. Each was a term which sought to mask the adoption of a premise which begged the question of what “marriage” means. The marriage law of many nations has always encompassed (and now encompasses) relations other than marriage as understood in Hyde v Hyde.

Other legal systems now provide for marriage between persons of the same sex. This may properly be described as being a recent development of the law of marriage in those jurisdictions. It is not useful or relevant for this Court to examine how or why this has happened. What matters is that the juristic concept of marriage (the concept to which s 51(xxi) refers) embraces such unions. They are consensual unions of the kind which has been described. The legal status of marriage, like any legal status, applies to only some persons within a jurisdiction.  The boundaries of the class of persons who have that legal status are set by law and those boundaries are not immutable.

When used in s 51(xxi), “marriage” is a term which includes a marriage between persons of the same sex.


According to these paragraphs it appears that the HCA would agree that although “marriage” in s 51 (xxi) is capable of including same-sex relationships, it would not include relationships such as flat mates and multi-partner arrangements.

Although the ACT legislation was held to be invalid by the HCA, importantly, at the same time the HCA decision has confirmed the constitutional power of Parliament to change the law and allow same-sex marriages.