Commonwealth v Australian Capital Territory

The High Court of Australia considered a dispute between the Commonwealth of Australia and the Australian Capital Territory concerning the validity of the *Marriage Equality (Same Sex) Act 2013* (ACT). The Commonwealth challenged the ACT legislation, which provided for marriage between two people of the same sex, on the grounds of inconsistency with Commonwealth law.

The central legal issues before the Court were whether the ACT Act was inconsistent with the *Marriage Act 1961* (Cth) within the meaning of section 28(1) of the *Australian Capital Territory (Self-Government) Act 1988* (Cth), and whether it was repugnant to the Commonwealth Act. The Court was also asked to determine the extent to which the ACT Act would be of no effect or void if found to be inconsistent or repugnant.

The Court reasoned that the *Marriage Act 1961* (Cth) defined marriage exclusively as the union of a man and a woman. This definition, enacted pursuant to the Commonwealth Parliament's constitutional power under section 51(xxi) of the Constitution, established a uniform national law on marriage. The *Marriage Equality (Same Sex) Act 2013* (ACT), by providing for same-sex marriage, created a legislative scheme that was incapable of operating concurrently with the Commonwealth Act. Consequently, the ACT Act was found to be inconsistent with the *Marriage Act 1961* (Cth) under section 28(1) of the *Australian Capital Territory (Self-Government) Act 1988* (Cth).

The Court declared that the whole of the *Marriage Equality (Same Sex) Act 2013* (ACT) was inconsistent with the *Marriage Act 1961* (Cth) and therefore of no effect. The Australian Capital Territory was ordered to pay the Commonwealth's costs.