Explain how international law is incorporated into Australian domestic law and analyse the scope of the external affairs power

What this dot point is asking

This dot point connects international law to the domestic system, so SCSA wants you to explain the two-step process by which a treaty becomes enforceable law in Australia and to analyse the constitutional power that makes implementation possible. The external affairs power is central because it is the main route for international law into Australian law.

Treaty-making and the gap with domestic law

Entering treaties is an executive act: the Commonwealth executive negotiates, signs and ratifies treaties on behalf of Australia, traditionally without needing parliamentary approval (though treaties are now tabled and reviewed by the Joint Standing Committee on Treaties). Crucially, Australia follows a dualist approach: international law and domestic law are separate systems. So ratifying a treaty binds Australia internationally but does not by itself create rights or obligations enforceable in Australian courts. Until Parliament legislates, the treaty has limited domestic legal effect.

Giving treaties domestic effect

To make a treaty enforceable domestically, Parliament passes an Act that incorporates its terms. The Racial Discrimination Act 1975, for instance, implements the Convention on the Elimination of All Forms of Racial Discrimination, and various environmental and human rights Acts implement other conventions. This legislation is what individuals and courts actually rely on. Without it, a treaty obligation may still influence the law indirectly, for example by informing the interpretation of ambiguous statutes or as a legitimate expectation, but it does not directly bind.

The external affairs power

The constitutional basis for implementing treaties is the external affairs power in section 51(xxix), which lets the Commonwealth make laws with respect to external affairs. The High Court has interpreted this power broadly to include implementing Australia's international treaty obligations. This is significant for federalism: a treaty can concern a subject that would otherwise be a residual state power, yet a Commonwealth law implementing it is valid under the external affairs power. The power therefore lets the Commonwealth reach into areas like the environment and human rights through the treaty route.

The Tasmanian Dam Case

The defining authority is the Commonwealth v Tasmania (1983), the Tasmanian Dam Case. Tasmania planned to dam a river in a World Heritage area; the Commonwealth, relying on the World Heritage Convention, legislated to stop it. The High Court upheld the Commonwealth law as a valid exercise of the external affairs power, holding that the Commonwealth could legislate to give effect to a genuine treaty obligation even on a matter (land use) normally within state control. There are limits: the law must give effect to a bona fide treaty obligation and be reasonably appropriate to that end. The case is essential because it shows the external affairs power expanding Commonwealth reach through international law.

Evaluating the system

When you analyse, note the tension. The system protects democratic accountability, because the executive cannot create domestic rights and duties alone; Parliament must legislate. But it also means Australia can be bound internationally while individuals have no domestic remedy until Parliament acts, which is why human rights treaties such as the ICCPR have limited direct effect in Australian courts. At the same time, the breadth of the external affairs power lets the Commonwealth implement treaties widely, shifting power away from the states, which is a recurring federalism concern.