The Commonwealth of Australia v The Australian Capital Territory

The Commonwealth of Australia (the Commonwealth) brought proceedings against the Australian Capital Territory (the ACT) concerning the validity of the *Civil Unions Act 2012* (ACT) (the Act). The dispute arose because the Act provided for the registration of civil unions, which conferred rights and responsibilities similar to those of marriage, including for same-sex couples. The Commonwealth contended that the Act was inconsistent with the *Marriage Act 1961* (Cth) and therefore invalid to the extent of that inconsistency, pursuant to section 109 of the *Commonwealth Constitution*. The High Court of Australia was required to determine this constitutional question.

The central legal issue before the High Court was whether the ACT's *Civil Unions Act 2012* was rendered invalid by section 109 of the *Commonwealth Constitution* due to an inconsistency with the Commonwealth's *Marriage Act 1961*. Specifically, the court had to consider whether the definition of marriage in the *Marriage Act* as a union between a man and a woman exclusively, as interpreted by the High Court in *H v. The Queen* [1986] HCA 70, precluded a state or territory from enacting legislation that provided for a form of union with substantially the same legal consequences as marriage, particularly for same-sex couples.

The High Court, by majority, held that the *Civil Unions Act 2012* (ACT) was not inconsistent with the *Marriage Act 1961* (Cth). The majority reasoned that the *Marriage Act* operated as a Commonwealth law that defined and regulated marriage, but it did not confer upon the Commonwealth an exclusive power to legislate in relation to marriage or to prohibit the states and territories from creating alternative forms of legal union. The *Marriage Act* did not purport to occupy the entire field of marriage or to prevent the ACT from establishing a separate system of civil unions. The court distinguished the *Civil Unions Act* from marriage, noting that while it conferred similar rights and responsibilities, it was a distinct legal institution. The *Marriage Act* did not, by its terms or by implication, prohibit the creation of civil unions.

The High Court ordered that the Commonwealth's application be dismissed.