This chapter examines the trade and commerce power. Section 51(i) of the Australian Constitution grants the Federal Parliament power to make laws with respect to two subject-matters: (1) international trade and commerce; and (2) inter-State trade and commerce.

This chapter examines the Federal Parliament as an institution through focusing on its composition. The Australian Constitution prescribes that the Federal Parliament consists of the monarch, a Senate and a House of Representatives. The Constitution provides that senators are chosen from each State but also provides that the laws may be enacted granting parliamentary representation to the Territories. The High Court has read these provisions together to permit senators to be chosen from the Territories. The Constitution also sets out various grounds which disqualify a person from being chosen or serving as a parliamentarian.

This chapter examines section 51(xxxi) of the Australian Constitution, which functions as: (1) a head of federal legislative power empowering the Commonwealth to compulsorily acquire property from individuals and States; and (2) as a limitation on federal legislative power restricting the power of the Commonwealth to acquire property otherwise than on just terms. The High Court has given a broad interpretation of the concept of ‘property’, which includes the full range of property rights recognised by the general law, such as real and personal property, intellectual property, and choses in action. The High Court has also given a broad interpretation to the concept of ‘acquisition’, but has emphasised that mere deprivation or taking of property without some countervailing benefit accruing to another does not amount to an acquisition.

This chapter examines an important limitation on federal power: the limited guarantee of religious freedom provided by section 116 of the Australian Constitution. Section 116 prohibits federal laws, but not State laws, from: (1) establishing any religion; (2) imposing any religious observance; and (3) prohibiting the free exercise of any religion. Section 116 also prohibits religious tests for holding any office or public trust under the Commonwealth, whether that religious test is imposed by law or otherwise. There are very few cases considering section 116, with the consequence that the case law is not well developed. Section 116 was included in the Australian Constitution to ensure that the Federal Parliament would not be able to pass laws in respect of religion. There had been a concern from some religious minorities that federal laws might be enacted requiring people to participate in mainstream Christian observances.

This chapter examines the scope of federal judicial power. Chapter III of the Australian Constitution sets out a comprehensive regime for the exercise of federal judicial power. This means that federal judicial power can be exercised only in the way prescribed by Chapter III. There is no comprehensive definition of ‘judicial power’, although there are some functions that are always judicial in nature and some functions that are never judicial in nature. Federal jurisdiction – that is, the exercise of federal judicial power – is limited to the subject-matters set out sections 75 and 76 of the Constitution and also limited to ‘matters’ respecting those subject-matters.

This chapter examines the executive power of the Commonwealth. The provisions of the Constitution concerning the structure of the Federal Executive Government and the exercise of federal executive power do not fully describe how the Federal Executive Government operates in practice. Those provisions need to be understood in light of the conventions of responsible government governing the actual operation of the Federal Executive Government and the exercise of its powers. The Federal Executive Government cannot be treated as if it is an ordinary legal person with capacity to act as it pleases subject only to the general law. The Federal Executive Government can only exercise powers which it lawfully possesses. Federal executive power includes powers derived from the Royal Prerogative, powers derived from Australia’s status as a nation, and powers conferred on the Federal Executive Government by statute.

This chapter examines two related heads of power: the immigration power in section 51(xxvii) and the aliens power in section 51(xix) of the Australian Constitution. Immigration is concerned with the act of a non-Australian entering into Australia and the process of an immigrant becoming absorbed into the Australian community so that they are no longer an immigrant. Whether a person is an immigrant is largely a question of fact. By contrast, alienage is a legal status. Within the limits of the concept of ‘alien’, Parliament has power to determine who is and is not an alien. The contemporary position is that an alien is anyone who is a non-citizen. The aliens power includes the power to take away citizenship so as to turn a citizen into an alien. The case law shows that all immigrants are aliens but that not all aliens are immigrants. Both heads of power can be used to regulate the conduct of individuals, including providing for their deportation. Because the meaning of the concepts involved is clearer, Parliament nowadays tends to rely on the aliens power to support legislation dealing with migration and related policy areas.

This chapter examines the legislative powers of the States. The chapter explains that the legislative powers of the States pre-date the Australian Constitution, were made subject to the Australian Constitution but otherwise continued in force at Federation, and were confirmed by the Australia Act 1986. In general terms, the States possess plenary legislative power that allows them to make and unmake any laws they want. That power extends to amending State Constitution Acts by ordinary legislation. The plenary power of the States is subject to the possibility of restrictive procedures that regulate the way in which certain types of laws must be passed, but which do not prohibit the passing of those laws. The States also have power under the Australian Constitution to refer power to make laws to the Commonwealth Parliament and thereby expand the practical scope of federal legislative power.

This chapter examines the extent to which detention otherwise than as punishment for a crime is constitutionally permissible. Chapter 17 explained that only Chapter III courts may exercise federal judicial power, and Chapter 16 explained that punishment is an exclusively judicial function. There is a general presumption that detention serves punitive purposes. It follows that a federal law may not authorise the Federal Executive Government to detain a person for punitive purposes otherwise than as a judicially-imposed punishment. A body of case law has developed explaining the extent to which detention otherwise than as punishment for a crime is constitutionally permissible. The basic proposition is that detention for non-punitive purposes is not judicial in character, and that this remains so even if the conditions of detention are prison-like or harsh. Detention must be limited to what is reasonably necessary for non-punitive purposes, otherwise the presumption that detention is punitive in character will apply and render the detention unconstitutional. Most of the case law concerns immigration detention, but the general principles are not limited to that context.

This chapter examines the guarantee section 92 provides for freedom of inter-State trade, commerce and intercourse. While the High Court previously interpreted section 92 as providing for two separate guarantees (one guaranteeing freedom of inter-State trade and commerce, and one guaranteeing freedom of inter-State intercourse) with different analytical frameworks, section 92 is now understood as being a composite provision having two limbs – the inter-State trade and commerce limb and the inter-State intercourse limb – with a common analytical framework for determining whether a law contravenes the provision. The guarantee of freedom of inter-State trade and commerce ensures free trade within Australia. It operates to invalidate discriminatory burdens of a protectionist kind imposed on inter-State trade and commerce. The guarantee of freedom of inter-State intercourse ensures freedom of movement from one State to another. It operates to invalidate all discriminatory burdens on inter-State intercourse. It also operates to invalidate disproportionate incidental burdens on inter-State intercourse.

This chapter examines key aspects of constitutional method. First, this chapter considers constitutional interpretation, which is concerned with working out what the terms and provisions of the Constitution mean and how they apply. Secondly, this chapter considers the technique of characterisation, which is concerned with working out whether a law is one with respect to a head of legislative power or a prohibition on legislative power. Finally, this chapter considers the nature and consequences of constitutional invalidity.