On 12^th December 2013 the Australian High Court handed down its unanimous decision in The Commonwealth v Australian Capital Territory. The Commonwealth (e.g. the federal State) challenged the validity of the Marriage Equality (Same Sex) Act 2013 enacted by the Australian Capital Territory (ACT), arguing that the Act was inconsistent with the Commonwealth Marriage Act 1961. The decision clarified questions of law regarding the nature of the constitutional power of the Commonwealth of Australia to make laws in respect to “marriage” and whether the exercise of that power in the Marriage Act 1961 was a complete and exhaustive law governing marriage in Australia.

The High Court decided that:

1. The constitutional power to make laws about marriage includes power to make laws about marriage between persons of the same sex. The Court referred to the purpose of the marriage power (uniformity within Australia), historical changes in the social institution of marriage, international variation in the laws of marriage (including same sex marriage reforms), and the fact that 19^th Century notions of marriage and judicial commentary about the meaning of marriage did not confine the scope of the marriage power.
2. The Commonwealth Marriage Act (as currently stands) is a complete statement of the law of marriage in Australia. The controversial 2004 amendments to the Marriage Act inserted a definition of marriage as “the union of a man and a woman to the exclusion of all others, voluntarily entered into for life” and provided expressly that a union solemnised in a foreign jurisdiction between persons of the same sex would not be recognised as a marriage in Australia (s88EA). The High Court concluded that the only conceivable purpose of the amendments was to demonstrate “that the federal law on marriage was to be complete and exhaustive” [57]. The Commonwealth has exercised its power to provide that the kind of marriage provided for in the Commonwealth Act is the only kind of marriage that may be formed or recognised in Australia. Therefore the ACT provisions are inconsistent with Commonwealth law and inoperative.

In Australia, the decision has clarified a long debated point of law. The High Court’s decision is significant because legal uncertainty was the basis for some politicians deciding to vote against same sex marriage bills. Notably, in Tasmania this led to the commissioning of a report from the Tasmanian Law Reform Institute (TLRI) to clarify the law. The TLRI declined to offer an opinion, noting the need for High Court determination. The High Court has now resolved the legal uncertainties.

The judiciary’s clarification of the law has placed the issue back in the hands of the legislature. Advocates for same sex marriage will now target their efforts squarely at the Commonwealth parliament. The Australian Greens immediately re-tabled a bill in the Senate when news of the High Court decision broke. This will bring the issue to the federal parliament in 2014. However, without a change of policy or granting of a conscience vote for members of the Coalition government, the bill is unlikely to pass.

The High Court’s decision makes it clear that the states and territories of Australia have no ability to enact laws enabling same sex marriage while the Commonwealth Marriage Act 1961 takes its current form. By defining marriage narrowly as a heterosexual union and also by excluding foreign same sex marriages from recognition in Australia, the Commonwealth has exercised its power over marriage broadly defined. The effect is that same sex marriage cannot be enabled in Australia unless the Commonwealth amends the Marriage Act 1961.

The High Court considered that international trends in relation to same sex marriage were relevant to its interpretation of the marriage power in the Australian Constitution. This demonstrates the transnational impact of reforms to marriage law at the domestic level. The nature and meaning of marriage has changed and the High Court noted that the social institution of marriage could not be confined to the meaning ascribed in Hyde v Hyde (1866) LR 1 P & D 130 which, among other things, limited marriage to heterosexual unions. The Court specifically referred to Canada, New Zealand, England and Wales as examples of the many countries where same sex marriage has been enabled, noting that this trend could not be ignored in defining “marriage” in the Constitution. The juristic concept of marriage was defined by the High Court as “a consensual union formed between natural persons in accordance with legally prescribed requirements which is not only a union the law recognises as intended to endure and be terminable only in accordance with law but also a union to which the law accords a status affecting and defining mutual rights and obligations” [33]. The legislature has the ability to limit who is entitled to marry in a particular jurisdiction, but the legislative power itself is broad. The High Court made it clear that the Commonwealth Parliament of Australia does have power to make a law for marriage between same sex couples.

Given international trends in similar common law countries, perhaps it is only a matter of time before a valid law for same sex marriage is made in Australia.