(a) No intersection between sections 494AB(1)(ca) and 198AHA
186 The distinction between powers and capacities is one which has a long history in the law relating to public executive action. The distinction is both sufficiently and clearly explained by Gageler J in Plaintiff M68 at [132] and [134]-[135] (footnotes omitted and noting that the reference to Brennan J is a reference to his Honour's reasons for judgment in Davis v Commonwealth [1988] HCA 63; 166 CLR 79 at 108):
Put in terms of [Professor Winterton's nomenclature, distinguishing between the "breadth" and "depth" of Commonwealth executive power], Brennan J referred exclusively to the depth of Commonwealth executive power when he noted that "an act done in execution of an executive power of the Commonwealth is done in execution of one of three categories of powers or capacities: a statutory (non-prerogative) power or capacity, a prerogative (non-statutory) power or capacity, or a capacity which is neither a statutory nor a prerogative capacity".
…
The tripartite categorisation posited by Brennan J has utility in highlighting, in relation to acts done in the exercise of a non-statutory power or capacity, the essential difference between an act done in the execution of a prerogative executive power and an act done in the execution of a non-prerogative executive capacity.
An act done in the execution of a prerogative executive power is an act which is capable of interfering with legal rights of others. An act done in the execution of a non-prerogative executive capacity, in contrast, involves nothing more than the utilisation of a bare capacity or permission, which can also be described as ability to act or as a "faculty". Such effects as the act might have on legal rights or juridical relations result not from the act being uniquely that of the Executive Government but from the application to the act of the same substantive law as would be applicable in respect of the act had it been done by any other actor. In this respect, the Executive Government "is affected by the condition of the general law". Subject to statute, and to the limited extent to which the operation of the common law accommodates to the continued existence of "those rights and capacities which the King enjoys alone" and which are therefore properly to be categorised as prerogative, the Executive Government must take the civil and criminal law as the Executive Government finds it, and must suffer the civil and criminal consequences of any breach.
187 Although Gageler J was there referring to the essential difference between non-statutory prerogative powers and non-statutory non-prerogative capacities, that essential difference applies equally in respect of statutory powers and statutory non-prerogative capacities. Whereas a statutory power is capable of interfering with legal rights, a statutory capacity does no more than confer a bare capacity, permission or faculty to engage in conduct, in the exercise of which the executive must "take the civil and criminal law as [it] finds it, and must suffer the civil and criminal consequences of any breach". Whether s 198AHA(2) confers a power or merely a capacity to engage in the relevant conduct is, of course, a question of statutory construction.
188 As to that question of construction, it is tolerably clear from his Honour's reasons in Plaintiff M68, particularly at [181], that Gageler J regarded s 198AHA(2) as limited to conferring statutory capacity on the Commonwealth (emphasis added):
Section 198AHA(3) is important in clarifying that s 198AHA(2) is directed to nothing other than ensuring that the Commonwealth has capacity and authority to take action and that it does not otherwise affect the lawfulness of that action. That is to say, s 198AHA(2) is directed to nothing other than conferring statutory capacity or authority on the Executive Government to undertake action which is or might be beyond the executive power of the Commonwealth in the absence of statutory authority. The section has no effect on the civil or criminal liability of the Executive Government or its officers or agents under Australian law or under the law of a foreign country. The lawfulness or unlawfulness of Executive Government action under Australian law or under the law of a foreign country conversely does not determine whether or not that action falls within the scope of the statutory capacity or authority conferred by the section.
189 Consistently with this understanding of his Honour's reasons, in explaining why principles derived from Chu Kheng Lim v Minister for Immigration, Local Government and Ethnic Affairs [1992] HCA 64; 176 CLR 1 are applicable to s 198AHA, Gageler J noted at [184] that he could "see no principled reason to distinguish between a law which confers a power of executive detention and a law which confers a capacity for executive detention so as to allow for the exercise of power from another legislative source." The reference to another legislative source presumably captures laws of the regional processing country mentioned in s 198AHA(1) that empower the Commonwealth or its officers to undertake acts in relation to which s 198AHA(2) confers capacity.
190 The Commonwealth parties submitted that Gageler J's reasons in Plaintiff M68 at [181], and in particular his general observation that s 198AHA "has no effect on the civil or criminal liability", should "be approached with some caution" because, so it was submitted, s 198AHA "can truly affect the lawfulness of an action". Indeed, the Commonwealth parties submitted that it did so in Plaintiff M68 because, on Gageler J's reasoning, the plaintiff's detention would otherwise have been unlawful (and presumably compensable in damages). However, the trite observation that capacity is a necessary ingredient of the validity (in a public law sense) of governmental action, which may be of decisive importance in, for instance, a false imprisonment claim, should not distract from what is presently relevant, which is that s 198AHA confers a capacity or authority, as distinct from a power, to engage in the relevant conduct to which it applies, in the exercise of which the Commonwealth takes the civil and criminal law as it finds it.
191 The passage of Gageler J's reasons in Plaintiff M68 at [181] extracted above was unanimously adopted in Plaintiff S195/2016 v Minister for Immigration and Border Protection [2017] HCA 31; 261 CLR 622 at [27]. It is also consistent with the plurality's reasons in Plaintiff M68. Relevantly, the plurality held there that the plaintiff was "detained in custody under the laws of Nauru" (at [32]) and that "the restrictions applied to the plaintiff are to be regarded as the independent exercise of sovereign legislative and executive power by Nauru" (at [34]), from which it followed that "the Commonwealth did not itself detain the plaintiff" (at [36]). Put another way, s 198AHA(2) did not provide the source of legislative power under which the plaintiff was detained: Nauruan law did. Although, in determining whether the Commonwealth's participation in the plaintiff's detention was supported by s 198AHA, the plurality subsequently referred (at [46]) to that provision ensuring the Commonwealth has "power to fund the [Regional Processing] Centre and the other services to be provided under these arrangements" (emphasis added), properly understood their Honours were referring to the Commonwealth's capacity to spend which, absent legislative authority, has been regarded as limited after Williams (No 1). This understanding is confirmed by the statement in the very next sentence of the plurality's reasons in Plaintiff M68, that "the authority in [s 198AHA(2)] would extend to permitting the Commonwealth to provide services to carry into effect the laws of Nauru" (emphasis added). Again, this reflects an understanding of s 198AHA as conferring a capacity or bare authority, with Nauruan law supplying any power or constraints on the performance of relevant activities on Nauru in respect of persons who have been taken there under Australia's regional processing arrangements.
192 Even were the matter free from authority, we would reach the same conclusion as a matter of ordinary statutory construction. The text of s 198AHA supports such a conclusion. That the authority conferred by s 198AHA(2) has the "inherent character" which distinguishes a capacity from a power (namely that its exercise is subject to the law and does not itself affect rights and liabilities: see Plaintiff M68 at [135]-[136] per Gageler J) is explicitly stated by the terms of s 198AHA(3). They provide that "[t]o avoid doubt, subsection (2) is intended to ensure that the Commonwealth has capacity and authority to take action, without otherwise affecting the lawfulness of that action" (emphasis added). It is also significant that s 198AHA(3) uses the language of "capacity and authority", rather than "power", to describe the operation of s 198AHA(2). The reference in the heading to s 198AHA to "power" cannot displace the actual language used in the operative parts of the provision even though the heading is a relevant aid to statutory construction: H v Minister for Immigration and Citizenship [2010] FCAFC 119; 188 FCR 393 at [72].
193 As mentioned above, relevant extrinsic materials support this construction. The 2015 Explanatory Memorandum states that s 198AHA(2) "does not purport to have any effect in itself on the rights of" people in the position of the applicants. The Statement of Compatibility with Human Rights attached to the 2015 Explanatory Memorandum similarly states that "[t]o the extent that the liberty of persons taken to regional processing countries is restrained in those countries, this is done under the laws of that country"; that s 198AHA(2) "confirms the ability of Australian officials … to take action to assist the foreign government in the regional processing country"; and that s 198AHA does "not otherwise provide authority for any restraint over the liberty of persons." Any tension between the last statement and the explicit inclusion by s 198AHA(5) of "exercising restraint over the liberty of a person" in the "action" authorised by s 198AHA(2) is resolved by reading "otherwise" in the Explanatory Memorandum as meaning otherwise than as provided by the relevant foreign country's laws. These statements are significant for two reasons. First, they confirm that s 198AHA(2) confers a statutory capacity only, and does not provide a source of power (capable of interfering with rights) to engage in the relevant activities. Secondly, they demonstrate that it was not contemplated that the inclusion of s 198AHA within Subdiv B would have the effect, by operation of s 494AB(1)(ca), of preventing litigants from instituting or continuing proceedings in courts (at least other than the High Court) which might be thought to constitute an "effect … on the rights of" people in the applicants' position.
194 Once it is appreciated that the "capacity and authority" conferred by s 198AHA(2) is limited to a statutory capacity (to adopt Brennan J's nomenclature in Davis at 108), or bare authority or permission, or faculty, to engage in certain activities, it follows that an exercise of that capacity cannot constitute "the performance or exercise of a function, duty or power under Subdivision B of Division 8 of Part 2 in relation to a transitory person". This is so for two primary reasons.
195 First, it is difficult to read the compound expression "function, duty or power" as encompassing a statutory capacity. As explained above a capacity, by its very nature, is to be distinguished from a power. Similarly, "function" implies a statutorily mandated responsibility, task or object, and "duty" implies a positive obligation; neither naturally describes the operation of a statutory capacity.
196 Secondly, and perhaps more significantly, even if the phrase is read distributively and "performance … of a function", or any other permutation, given a broad meaning which encompasses the exercise of a statutory capacity conferred by s 198AHA, any such exercise would not constitute the "performance or exercise of a function, duty or power under" the relevant subdivision of the Migration Act. In Griffith University v Tang [2005] HCA 7; 221 CLR 99, the plurality of the High Court (Gummow, Callinan and Heydon JJ) observed at [29] that the adoption of the statutory language "decision of an administrative character made … under an enactment" directed attention "to the source of the power of the decision-makers." That is the natural way in which one reads "under" in s 494AB(1)(ca). In explicating what relationship between a "decision of an administrative character" and a relevant "enactment" was entailed by that statutory language in its context, the plurality in Tang rhetorically asked at [80]: "does the decision in question derive from the enactment the capacity to affect legal rights and obligations?" The plurality held, at [81], that "[i]f the decision derives its capacity to bind from contract or some other private law source, then the decision is not 'made under' the enactment in question". At [82], the plurality stated:
For these reasons, a statutory grant of a bare capacity to contract does not suffice to endow subsequent contracts with the character of having been made under that enactment. A legislative grant of capacity to contract to a statutory body will not, without more, be sufficient to empower that body unilaterally to affect the rights or liabilities of any other party. The power to affect the other party's rights and obligations will be derived not from the enactment but from such agreement as has been made between the parties. A decision to enter into a contract would have no legal effect without the consent of the other party; the agreement between the parties is the origin of the rights and liabilities as between the parties.
See also, to similar effect, at [18] per Gleeson CJ.
197 The plurality's conclusion in Tang in relation to the phrase "under an enactment" was influenced by the subject matter of the relevant statutory expression being "administrative decisions". Their Honours regarded it as relevant to inquire at [79] into "[w]hat is it, in the course of administration, that flows from or arises out of the decision taken so as to give that significance which has merited the legislative conferral of a right of judicial review", which they identified in "general terms" at [80] as "the affecting of legal rights and obligations". The same answer should be given, in the legislative context relevant here, to the question what is it that flows from or arises out of the exercise of a relevant "function, duty or power" - significantly, in relation to a transitory person - which establishes the sort of relationship with a proceeding that merits the legislative exclusion of that proceeding by s 494AB(1)(ca) from those which can be instituted or continued in courts other than the High Court. Proceedings of the kind contemplated by s 494AB(1) involve, at their core, an exercise of judicial power to resolve contested rights and liabilities, and the character of those proceedings derives from what rights and liabilities are sought to be so determined. Properly construed, therefore, a proceeding is related to the exercise of a function, duty or power under the relevant subdivision of the Migration Act only if that subdivision gives to the relevant performance or exercise of a function, duty or power in relation to a transitory person the capacity to affect the rights of the transitory person which are sought to be determined in the proceeding.
198 As explained above, s 198AHA(2) does not give to the actions to which it relates the ability to interfere with the rights of transitory persons, because it is not a source of power to engage in those actions. Any actions alleged in the present case which constitute an exercise of the capacity conferred by that section are not, therefore, to be regarded as "under" the Migration Act, or any part of it, for the purposes of s 494AB(1)(ca). To the extent any of those actions are to be regarded as "under" anything, in the sense of that thing giving to the Commonwealth government a source of power to engage in the activities and giving that engagement the capacity to interfere with rights, they could be regarded as being under applicable laws of Nauru or an applicable aspect of the non-statutory executive power.
199 Section 198AHA does not confer any statutory powers, duties or functions on the Commonwealth, but rather confers a bare capacity that enables the Commonwealth to be conferred with powers or functions or duties under the laws of a regional processing country.
200 As the Commonwealth parties pointed out, in the task of statutory construction a statute which is amended and an amending statute are to be read together as a combined statement of the will of the legislature (see Commissioner of Stamps (SA) at 463, Seller at [100] and s 11B(1) of the Acts Interpretation Act 1901 (Cth)). The Commonwealth parties submitted that s 494AB had to be construed in the light of the 2015 amendment which inserted s 198AHA, retrospective to 18 August 2012. Those submissions should be accepted.
201 That acceptance does not, however, change the nature of the interaction between ss 494AB(1)(ca) and 198AHA. For the above reasons, as a matter of statutory construction, the capacity or authority conferred by s 198AHA(2) does not intersect with s 494AB(1)(ca) in any manner relevant to the present proceedings.
202 The Melbourne cohort also submitted, in the alternative, that s 198AHA does not apply to persons such as them who have already been determined to be refugees. It is unnecessary to determine this alternative contention having regard to our reasoning and conclusion above.