The Australian Capital Territory has recently passed legislation which enables same-sex and intersex couples to marry under ACT state law. Under Australian Federal law, the power to make laws in relation to marriage belongs exclusively to the Federal Government.

The ACT State Marriage Equality Act has addressed this conflict by limiting the application of the State Act to adult couples who are ineligible to marry under Federal law, subject to exclusions such as marriage between relatives (including adopted relatives), similar to those contained in the Federal Marriage Act.

Unsurprisingly, the Federal Government has filed an Application in the original jurisdiction of the High Court of Australia challenging the validity of the ACT Marriage Equality Act, which is listed for a procedural hearing on 4 November 2013. A full hearing of the matter is reportedly likely to take place in December 2013, and is likely to attract significant media attention. For both family and constitutional lawyers, the written reasons for judgment are likely to be of particular interest, as the legisltation was drafted with the assistance of academic Professor George Williams, an expert in constitutional law.