The Commonwealth of Australia v The Australian Capital Territory

The Commonwealth of Australia (the Commonwealth) sought declarations and injunctions against the Australian Capital Territory (the ACT) concerning the validity of the *Civil Unions Act 2012* (ACT) and the *Marriage Act 1961* (Cth). The Commonwealth contended that the ACT legislation, which provided for the registration of civil unions and conferred rights and obligations similar to those under marriage, was inconsistent with the *Marriage Act 1961* (Cth) and therefore invalid under section 109 of the *Constitution*. The matter was heard by the High Court of Australia.

The central legal issue before the High Court was whether the *Civil Unions Act 2012* (ACT) was inconsistent with the *Marriage Act 1961* (Cth), and if so, whether the ACT Act was rendered invalid by operation of section 109 of the *Constitution*. This required the Court to consider the scope and effect of the Commonwealth's legislative power to make laws with respect to marriage, as conferred by section 51(xxi) of the *Constitution*, and the nature of the rights and obligations created by the ACT legislation.

French CJ held that the *Marriage Act 1961* (Cth) defined marriage exclusively as a union between a man and a woman. His Honour reasoned that the ACT's *Civil Unions Act 2012* created a legal status and associated rights and obligations that were substantially co-extensive with marriage, but were available to same-sex couples and opposite-sex couples. This created a situation where the ACT legislation purported to confer a status that was, in substance, marriage, but defined differently and available to a wider class of persons than that permitted by the Commonwealth *Marriage Act*. Consequently, His Honour found that the ACT Act was inconsistent with the Commonwealth *Marriage Act* and therefore invalid under section 109 of the *Constitution*.

The High Court made declarations that the *Civil Unions Act 2012* (ACT) was inconsistent with the *Marriage Act 1961* (Cth) and invalid to the extent of the inconsistency. The Court also granted injunctions restraining the ACT from registering civil unions under the impugned Act.