The External Affairs Power in Australia
Introduction
The external affairs power contained in s 51(xxix) of the Constitution is one of the most expansive and controversial sources of Commonwealth legislative authority. It empowers the Commonwealth Parliament to make laws with respect to “external affairs.” The High Court has interpreted this power broadly to encompass three distinct categories: matters geographically external to Australia, relations with other countries, and the implementation of international treaties and customary international law. The power has been a primary vehicle for the expansion of Commonwealth authority into areas of traditional State responsibility, particularly in environmental protection, human rights, and industrial relations.
The Geographical External Affairs Power
The first category of the external affairs power covers matters and things geographically external to Australia. In Polyukhovich v Commonwealth (1991) 172 CLR 501 (the War Crimes Act Case), the High Court upheld the validity of the War Crimes Act 1945 (Cth), which criminalised war crimes committed in Europe during World War II by persons who later became Australian residents. The Court held, by majority, that s 51(xxix) extends to any matter, person, or thing that is physically external to Australia. Mason CJ, Deane J, and Gaudron J held that the power is not limited by any requirement of a “sufficient connection” between Australia and the external matter — the mere fact of externality is enough to attract Commonwealth legislative power. Brennan J and Toohey J agreed in the result but held that some connection to Australia was required. The broad interpretation of the geographical limb was confirmed in XYZ v Commonwealth (2006) 227 CLR 532, which upheld the validity of laws criminalising sexual activity by Australian citizens with children overseas. The Court held by majority that the external affairs power supports laws prohibiting conduct outside Australia by Australian citizens and residents, regardless of whether the conduct is lawful in the country where it occurs.
Relations With Other Countries
The second category of the external affairs power covers matters affecting relations with other countries. In Koowarta v Bjelke-Petersen (1982) 153 CLR 168, the High Court considered whether the Racial Discrimination Act 1975 (Cth), which implemented the International Convention on the Elimination of All Forms of Racial Discrimination, was supported by the external affairs power. Stephen J, Mason J, Murphy J, and Brennan J held that the Commonwealth could implement the treaty under the external affairs power because the subject matter of the treaty was of international concern. Gibbs CJ, Aickin J, and Wilson J dissented, holding that the power did not extend to the implementation of treaties on matters that were otherwise within State competence.
The “international concern” test was subsequently overtaken by the broader approach adopted in the Tasmanian Dam Case (see below). However, the “relations with other countries” limb remains relevant for matters that do not involve treaty obligations, such as the establishment of diplomatic relations, the conduct of foreign policy, and the regulation of diplomatic and consular immunities.
Implementation of Treaties
The third and most significant category of the external affairs power is the power to implement international treaties to which Australia is a party. The scope of this power was dramatically expanded in Commonwealth v Tasmania (1983) 158 CLR 1 (the Tasmanian Dam Case), one of the most important constitutional decisions in Australian history. The case concerned a challenge to the validity of the World Heritage Properties Conservation Act 1983 (Cth), enacted to prevent the construction of the Franklin Dam in Tasmania by prohibiting certain activities on the Gordon River and the Franklin River, which had been listed under the Convention for the Protection of the World Cultural and Natural Heritage. The Commonwealth argued that the legislation was supported by the external affairs power because it implemented an international treaty obligation.
A majority of the High Court (Mason J, Murphy J, Brennan J, and Deane J) upheld the legislation. Mason J held that the external affairs power extends to the implementation of any international treaty obligation entered into in good faith, regardless of the subject matter of the treaty. The only requirement is that the legislation be appropriate and adapted to the implementation of the treaty obligation. Brennan J held that the law must be “reasonably capable of being considered appropriate and adapted to the treaty obligation.” The effect of the Tasmanian Dam Case was to confirm that the Commonwealth could use the external affairs power to legislate on any subject, provided the legislation implemented a treaty obligation. This enabled the Commonwealth to bypass the limitations of its enumerated heads of power by entering into treaties and then enacting implementing legislation.
Limits on the External Affairs Power
Despite its breadth, the external affairs power is subject to limits. First, the treaty must be genuine — it must not be a colourable attempt to acquire legislative power over a subject otherwise outside Commonwealth competence. In Richardson v Forestry Commission (1988) 164 CLR 261, the High Court held that a treaty is genuine if it has been entered into in good faith and deals with a matter of international concern. The Court will not inquire into the motives of the executive in entering into a treaty.
Second, the implementing law must be appropriate and adapted to the treaty obligation. In Victoria v Commonwealth (1996) 187 CLR 416 (the Industrial Relations Act Case), the High Court considered the validity of the Industrial Relations Act 1988 (Cth), which comprehensively regulated industrial relations to implement a range of International Labour Organization conventions. The Court held that the Act was invalid in part because it went beyond what was required to implement the conventions. Brennan CJ, Toohey J, Gaudron J, McHugh J, and Gummow J held that the law must conform to the treaty — it must not impose obligations that are inconsistent with, or go beyond, the treaty’s requirements. The “appropriate and adapted” test requires a proportionality analysis: the law must be reasonably capable of being considered appropriate and adapted to the treaty obligation.
Third, the treaty must not be a sham — it must actually impose obligations or confer rights. A treaty that is merely aspirational or hortatory may not provide a sufficient basis for legislation under the external affairs power.
Customary International Law
The external affairs power also supports the implementation of customary international law — rules of international law derived from the general practice of states accepted as law. In Nulyarimma v Thompson (1999) 165 ALR 621, the High Court held that customary international law does not become part of Australian domestic law without legislative implementation. However, the Commonwealth may legislate to implement customary international law under the external affairs power, and such legislation will be valid provided it is appropriate and adapted to the implementation of the customary rule.
Matters of International Concern
In Koowarta v Bjelke-Petersen (1982) 153 CLR 168, a plurality of the High Court recognised that the external affairs power extends to matters of international concern, even if they are not the subject of a treaty obligation. This category includes matters that are inherently international in character or that affect Australia’s relations with other countries. However, the scope of this category remains uncertain, as subsequent cases have focused on the implementation of treaty obligations rather than on matters of international concern per se.
The External Affairs Power and Human Rights
The external affairs power has been the primary constitutional basis for the enactment of human rights legislation in Australia, including the Racial Discrimination Act 1975 (Cth), the Sex Discrimination Act 1984 (Cth), the Disability Discrimination Act 1992 (Cth), and the Age Discrimination Act 2004 (Cth). These Acts implement Australia’s obligations under international human rights treaties. The external affairs power has also been used to enact legislation on extradition (Vasiljkovic v Commonwealth (2006) 227 CLR 614) and mutual assistance in criminal matters. The breadth of the power means that the Commonwealth can effectively legislate on any subject that is the subject of an international treaty, making the external affairs power a potential vehicle for the implementation of a comprehensive human rights framework.