The Executive and the External Affairs Power: Does the Executive's Prerogative Power to Vary Treaty Obligations Qualify Parliamentary Supremacy?

• Author: Zaccary Molloy Mencshelyi, Stephen Puttick and Murray Wesson
• Position: JD candidate, Law School, The University of Western Australia/JD candidate, Law School, The University of Western Australia/Senior Lecturer, Law School, The University of Western Australia
• Pages: 286-303

THE EXECUTIVE AND THE EXTERNAL AFFAIRS

POWER: DOES THE EXECUTIVE’S PREROGATIVE

POWER TO VARY TREATY OBLIGATIONS

QUALIFY PARLIAMENTARY SUPREMACY?

Zaccary Molloy Mencshelyi,* Stephen Puttick† and Murray Wesson‡

The Commonwealth Parliament is conferred legislative competence to implement

treaty obligations by the external affairs power. What is the status of implementing

legislation if the executive subsequently exercises its power to vary Australia’s

treaty obligations, and where that legislation cannot otherwise be constitutionally

supported? This comment argues that the external affairs power should be

understood as waxing and waning analogously to the defence power. The result is

that the executive may undermine the validity of implementing legislation by

varying treaty obligations. However, the sense of unease engendered by this

conclusion may, to some extent, be mitigated by implying a legislative intention

that implementing legislation should not endure beyond the facts that support its

validity.

I INTRODUCTION

Few propositions are as well entrenched as the claim that the executive, in the

exercise of its prerogative powers, cannot displace statute law or common law.

This proposition is supported by an abundance of authority stretching back to

the Glorious Revolution of 1688. As the Supreme Court of the United Kingdom

recently observed in

R (on the application of Miller) v Secretary of State for

Exiting the European Union

, ‘it is a fundamental principle of the UK

constitution that, unless primary legislation permits it, the Royal prerogative

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* JD candidate, Law School, The University of Western Australia.

† JD candidate, Law School, The University of Western Australia.

‡ Senior Lecturer, Law School, The University of Western Australia. The authors wish to acknowledge

that the question explored in this comment was inspired by the 2017 Sir Harry Gibbs Constitutiona l

Law Moot problem. Zaccary Molloy Mencshelyi and Stephen Puttick were members of the UWA Law

School team and Murray Wesson was the team coach. In accordance with competition rules, the

authors commenced collaborative work on the comment only after the conclusion of the moot

competition. The authors also thank Isabel Inkster for her insights.

[2018]

The Executive and the External Affairs Power

287

does not enable ministers to change statute or common law.’1 Similarly, in the

Australian context, Isaacs J held in

R v Kidman

that the ‘executive cannot

change or add to the law; it can only execute it.’2 The proposition is sourced in

both the legislative supremacy of Parliament and the separation of powers.3 It

is, Thomas Poole argues, an axiomatic rule about the institutional allocation of

public power that does not admit of balancing or deference.4

Yet, under the

Commonwealth Constitution

, this proposition may be

subject to an intriguing qualification in the context of treaty amendment or

withdrawal — an issue that has recently been the subject of considerable

discussion in other jurisdictions.5 In terms of the

Commonwealth Constitution

,

treaties are implemented pursuant to the external affairs power.6 The

ratification of a treaty generates legislative competence on the part of the

Commonwealth Parliament, with the validity of domestic legislation that

implements a treaty depending upon its conformity with that treaty.7 But, what

is the status of such legislation if the executive subsequently exercises the

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1 [2017] UKSC 5 (24 January 2017) [50] (Lord Neuberger P, Lady Hale DP, Lord Mance SCJ, Lord

Kerr SCJ, Lord Clarke SCJ, Lord Wilson SCJ, Lord Sumption SCJ and Lord Hodge SCJ).

2 (1915) 20 CLR 425, 441 cited with approval by French CJ in

Williams v Commonwealth (No 1)

(2012) 284 CLR 156, 187.

3 In

New South Wales v Commonwealth

(1915) 20 CLR 54, Isaacs J (at 90) referred to the proposition

that the ‘legislature makes, the executive executes, and the judiciary construes the law’ as the

‘dominant principle of demarcation’ of the

Constitution

.

4 Thomas Poole, ‘Losing our Religion? Public Law and Brexit’ on UK Constitutional Law Association,

UK Constitutional Law Association

(2 December 2016) <

https://ukconstitutionallaw.org/2016/12/02/thomas-poole-losing-our-religion-public-law-and-

brexit/>.

5 In

R (on the application of Miller) v Secretary of State for Exiting the European Union

[2017] UKSC

5 (24 January 2017), a majority of the Supreme Court of the United Kingdom held that legislation was

required prior to ministers issuing a notification pursuant to Article 50 of the

Treaty on European

Union for the United Kingdom

to withdraw from the European Union. Similarly, in South Africa in

Democratic Alliance v Minister of International Relations and Cooperation

2017 (3) SA 212 (GP),

a

Full Bench of the High Court found that a notice of withdraw from the

Rome Statute of the

International Criminal Court

was invalid given that it had not been preceded by parliamentary

approval and repeal of the implementation Act. This led the South African government to abandon its

attempt to withdraw from the

Rome Statute

. See, eg, Max du Plessis and Guenael Mettraux, ‘South

Africa’s Failed Withdrawal from the Rome Statute: Politics, Law, and Judicial Accountability’ (2017)

15

Journal of International Criminal Justice

361.

6 Section 51(xxix) of the

Commonwealth of Australia Constitution Act

: ‘The Parliament shall, subject

to this Constitution, have power to make laws for the peace, order, and good government of the

Commonwealth with respect to external affairs.’

7 See, eg,

Victoria v Commonwealth (Industrial Relations Act Case)

(1996) 187 CLR 416, 486

(Brennan CJ, Toohey, Gaudron, McHugh and Gummow JJ).