Glossary of Australian Constitutional Law Terms

Introduction

This glossary defines key terms in Australian constitutional law, the foundational legal framework of the Commonwealth of Australia. The Commonwealth Constitution (formally the Commonwealth of Australia Constitution Act 1900 (UK)) establishes a federal commonwealth under a constitutional monarchy, distributing legislative power between the Commonwealth and the six original States. The High Court of Australia, established under s 71, sits as the final arbiter of constitutional meaning, having developed a distinctive body of doctrine since its first sittings in 1903.

A

Acquired Power — See Section 51(xxxi).

Acquisition on Just Terms — The power of the Commonwealth to acquire property is constrained by s 51(xxxi) of the Constitution, which requires that any acquisition be on “just terms.” This provision operates as a constitutional guarantee of compensation, not merely a grants of power. The High Court has held that “acquisition” extends beyond the vesting of full legal title to encompass any substantial deprivation of proprietary rights: ICM Agriculture v Commonwealth (2009) 240 CLR 140. The “just terms” requirement mandates full, fair compensation assessed as at the date of acquisition.

Amendment — See Section 128 Amendment.

Australia Acts 1986 — A pair of statutes — one Commonwealth, one United Kingdom — that terminated the remaining legislative authority of the UK Parliament over Australia, abolished appeals from Australian courts to the Privy Council, and declared that the ultimate sovereign within Australia resides in the Australian people. The Acts completed Australia’s constitutional independence. Section 15 of the Australia Act 1986 (Cth) expressly declares that no future UK Act shall extend to Australia as part of its law.

Autochthonous Expedient — A term coined by Sir Owen Dixon to describe the distinctly Australian constitutional innovation of vesting federal jurisdiction in state courts, rather than establishing a separate system of federal courts. The Australian Constitution, unlike that of the United States, permits the Commonwealth Parliament to invest state courts with federal jurisdiction (s 77(iii)). This expedient integrates the state and federal judicial systems while maintaining the institutional framework for the Separation of Judicial Power.

C

Chapter III Court — A court established under or invested with jurisdiction by Chapter III of the Constitution. The defining feature of a Chapter III court is the requirement of institutional integrity: the court must be, and must appear to be, independent and impartial. The High Court has held that a Chapter III court cannot exercise non-judicial power that would compromise its institutional integrity: Kable v Director of Public Prosecutions (NSW) (1996) 189 CLR 51 (applied to state courts); Forge v Australian Securities and Investments Commission (2006) 228 CLR 45.

Commonwealth Constitution — The supreme law of the Commonwealth of Australia, enacted as s 9 of the Commonwealth of Australia Constitution Act 1900 (UK) (63 & 64 Vict c 12). The Constitution establishes a federal system of government, with legislative power distributed between the Commonwealth Parliament and the State Parliaments. It creates a bicameral Federal Parliament (the House of Representatives and the Senate), an executive government headed by the Governor-General as the Queen’s representative, and a federal judicature culminating in the High Court of Australia. The Constitution may be amended only by a referendum under s 128, requiring a double majority.

Corporations Power — Section 51(xx) of the Constitution empowers the Commonwealth to make laws with respect to “foreign corporations, and trading or financial corporations formed within the limits of the Commonwealth.” The High Court has given this power a broad interpretation: New South Wales v Commonwealth (1990) 169 CLR 482 (the Corporations Case), upholding the Corporations Act 1989 (Cth) as a valid exercise of power. The power extends to the regulation of the internal management, trading activities, and external relationships of constitutional corporations.

Crown — The legal embodiment of executive authority in Australia. The Commonwealth and each State share the same Crown as a matter of legal doctrine, though the Crown “acts in right of” each polity. The Governor-General and State Governors exercise the Crown’s prerogative powers, subject to constitutional and statutory limitations. The concept of the Crown also underpins the prerogative, the historic residue of executive authority recognised by the common law.

D

Double Majority — The requirement under s 128 of the Constitution for a successful referendum proposal to secure (a) a majority of votes nationwide, and (b) a majority of votes in a majority of States (i.e., at least four of the six States). This dual requirement ensures that no amendment can be carried solely by populous States and reflects the federal compact.

E

Engineers’ Case — Amalgamated Society of Engineers v Adelaide Steamship Co Ltd (1920) 28 CLR 129. A watershed decision in which the High Court rejected the doctrines of Reserved State Powers and implied intergovernmental immunities, holding that the Constitution must be interpreted according to its ordinary meaning, without reading in limitations not expressed in the text. The case established the modern approach to constitutional interpretation and enabled the expansive reading of Commonwealth legislative powers that followed.

Executive Council — The formal body, comprising the Governor-General and Commonwealth Ministers, through which the Governor-General exercises executive authority. The Federal Executive Council is established by s 62 of the Constitution. Its principal function is to provide advice to the Governor-General on the exercise of the Crown’s executive powers, though in practice its decisions are formal ratifications of Cabinet decisions.

External Affairs Power — Section 51(xxix) of the Constitution empowers the Commonwealth to make laws with respect to “external affairs.” This power has three recognised limbs: (a) matters geographically external to Australia; (b) relations with other countries; and (c) the implementation of international treaties and customary international law. The last limb was given a broad construction in Commonwealth v Tasmania (1983) 158 CLR 1 (the Tasmanian Dam Case), which held that the power supports legislation implementing any bona fide treaty obligation. The power is subject only to implied constitutional limitations and the requirement that the law be capable of being considered “proportionate” to the treaty obligation.

F

Federal Parliament — The bicameral legislature of the Commonwealth, established under Chapter I of the Constitution (ss 1–60). It consists of the Queen (represented by the Governor-General), the Senate (the upper house, with equal representation from each State — 12 Senators per State, plus two each from the Territories), and the House of Representatives (the lower house, with seats distributed according to population, with each State guaranteed at least five members). The Senate acts as a “States’ house” and a house of review, while the House of Representatives forms government.

G

Governor-General — The representative of the Crown in right of the Commonwealth, appointed by the Queen on the advice of the Prime Minister (s 2 of the Constitution). The Governor-General exercises the executive power of the Commonwealth (s 61) and performs ceremonial, constitutional, and reserve powers. The office-holder acts on the advice of Ministers in ordinary circumstances but retains certain reserve powers — including the power to dismiss a Prime Minister who has lost the confidence of the House (though the exercise of this power following the 1975 dismissal of Prime Minister Gough Whitlam remains controversial).

H

High Court of Australia — Australia’s final court of appeal and the guardian of the Constitution. Established by s 71 of the Constitution, it comprises seven Justices (the Chief Justice and six puisne Justices). Its original jurisdiction includes matters arising under the Constitution (s 76(i)), matters between States (s 75(iii)), and matters in which a constitutional writ is sought (s 75(v)). Its appellate jurisdiction (subject to the grant of special leave under s 35A of the Judiciary Act 1903 (Cth)) extends to all Australian federal and state courts.

I

Implied Freedom of Political Communication — An implied constitutional freedom derived from the system of representative and responsible government established by the Constitution. First recognised in Australian Capital Television v Commonwealth (1992) 177 CLR 106 (ACTV) and Nationwide News v Wills (1992) 177 CLR 1, the freedom protects communication about political and governmental matters from legislative abridgment. The test for validity, reformulated in McCloy v New South Wales (2015) 257 CLR 178 and Brown v Tasmania (2017) 261 CLR 328, asks whether the law burdens the freedom and, if so, whether it serves a legitimate purpose compatible with representative government and is proportionate.

Indefeasibility of Title — A principle of real property law (Torrens system) that a registered proprietor’s title to land cannot be defeated by prior unregistered interests (save for statutory exceptions). While originating in property law rather than constitutional law, it is frequently referenced in Australian legal discourse for its significance to the system of land registration established by Sir Robert Torrens in 1858.

Intergovernmental Immunities — The constitutional protection of States from Commonwealth legislative interference, and vice versa. After the Engineers’ Case (1920) repudiated the earlier implied immunity doctrine, the High Court has recognised a limited implied immunity for the States from Commonwealth laws that would “destroy or curtail” their capacity to function as independent polities: Melbourne Corporation v Commonwealth (1947) 74 CLR 31; Austin v Commonwealth (2003) 215 CLR 185. The Melbourne Corporation Principle now protects the States’ “structural integrity and capacity to function.”

M

Mabo — Mabo v Queensland (No 2) (1992) 175 CLR 1. The landmark decision in which the High Court recognised the native title rights of Indigenous Australians at common law. The Court rejected the doctrine of terra nullius (that Australia was “land belonging to no one” before British settlement) and held that Indigenous Australians had a system of customary law and land tenure that survived the Crown’s acquisition of radical title. The case established that native title exists at common law, subject to extinguishment by valid executive or legislative action, and is recognised under the Native Title Act 1993 (Cth).

Melbourne Corporation Principle — See Intergovernmental Immunities.

N

Nationhood Power — An implied constitutional power, derived from ss 51(xxxix) and 61 of the Constitution, that enables the Commonwealth to act in matters of “national concern” or “national emergency” where the subject matter is peculiarly within the province of the national government. The power supports Commonwealth legislation addressing matters of national significance that fall outside the enumerated heads of legislative power: Davis v Commonwealth (1988) 166 CLR 79 (upholding the Australian Bicentennial Authority Act).

P

Prerogative — The residue of discretionary executive authority recognised by the common law as belonging to the Crown. The executive power of the Commonwealth (s 61) extends to the exercise of the prerogative, subject to statutory abrogation. Relevant prerogative powers include the power to declare war and make peace, the power to enter treaties, the power to appoint and dismiss Ministers, and the prerogative of mercy.

R

Radical Title — The legal concept that upon British settlement of Australia, the Crown acquired “radical title” to all land — a ultimate sovereign title — but not full beneficial ownership. In Mabo v Queensland (No 2) (1992), the High Court held that radical title is a “logical postulate” of sovereignty that does not necessarily displace Indigenous customary land tenure, thereby enabling the recognition of native title.

Reserved State Powers — A doctrine of constitutional interpretation, rejected in the Engineers’ Case (1920), that held that the Commonwealth’s enumerated legislative powers should be read narrowly so as to “reserve” unexpressed areas of legislative power to the States. The doctrine was associated with the early High Court under Chief Justice Sir Samuel Griffith and Justice Sir Edmund Barton. Its rejection opened the way for the broad interpretation of Commonwealth powers.

S

Section 51 — The principal provision in the Constitution enumerating the legislative powers of the Commonwealth Parliament. Section 51 comprises 40 paragraphs (s 51(i)–(xxxix)), conferring power over specific subject matters including trade and commerce (s 51(i)), taxation (s 51(ii)), defence (s 51(vi)), external affairs (s 51(xxix)), and corporations (s 51(xx)). The State Parliaments retain residual legislative power over subjects not enumerated in s 51 (s 106–108 of the Constitution).

Section 109 Inconsistency — The constitutional provision (s 109) that Commonwealth laws prevail over State laws to the extent of any inconsistency. A State law is inconsistent with a Commonwealth law where: (a) it is impossible to obey both laws simultaneously; (b) the Commonwealth law covers the field and evinces an intention to do so exclusively; or (c) the Commonwealth law confers a right that the State law purports to remove or diminish. The High Court has given the provision a broad operation.

Section 128 Amendment — The mechanism for amending the Constitution. A proposed amendment must be approved by an absolute majority of each House of the Federal Parliament (or, in limited circumstances, by one House twice), and then submitted to a referendum. The referendum requires a double majority. No amendment has been achieved without bipartisan support.

Separation of Judicial Power — The constitutional doctrine that Chapter III of the Constitution mandates a strict separation of judicial power from legislative and executive power. Federal judicial power may be exercised only by Chapter III courts (Boilermakers’ Case: R v Kirby; Ex parte Boilermakers’ Society of Australia (1956) 94 CLR 254). State courts, while not directly subject to the federal separation, must retain their “institutional integrity” as repositories of federal jurisdiction: Kable v Director of Public Prosecutions (NSW) (1996) 189 CLR 51. This doctrine has been applied to invalidate legislation that would require state courts to exercise non-judicial functions incompatible with their constitutional role.

T

Tasmanian Dam Case — Commonwealth v Tasmania (1983) 158 CLR 1. A landmark decision in which the High Court upheld the Commonwealth’s World Heritage (Properties Conservation) Act 1983 (Cth) as a valid exercise of the External Affairs Power (s 51(xxix)). The case concerned the construction of a dam on the Gordon River in Tasmania and established that the external affairs power extends to the implementation of international treaties, including those concerning environmental and cultural heritage protection.

Terra Nullius — The legal fiction that Australia was “land belonging to no one” at the time of British settlement, thereby justifying the acquisition of sovereignty by settlement rather than by conquest or cession. The doctrine was effectively overruled by the High Court in Mabo v Queensland (No 2) (1992), which recognised that Indigenous Australians had a system of law and land tenure predating British sovereignty, though the Court confirmed that the Crown acquired sovereignty (and radical title) upon settlement.