Secretary, Department of Social Services v Vader

2. BACKGROUND AND LEGISLATION 13 The background facts were largely not in contest. They are summarised at [1]-‍[14] of the Primary Judgment. Given the reasons why the appeal must be dismissed, they can be shortly stated here.

2.1 Mr Vader's circumstances and the parties' position with respect to Article 1(1)(i) 14 First, the term "laws" is defined in Article 1(1)(e) to mean "as regards the United States, the laws and regulations specified in subparagraph 1(a) of Article 2". Article 2(1)(a) provides that: 1. For the purpose of this Agreement, the applicable laws are: (a) As regards the United States, the laws governing the Federal old-age, survivors, and disability insurance program: - Title II of the Social Security Act and regulations pertaining thereto, except sections 226, 226A and 228 of that title and regulations pertaining to those sections, - Chapters 2 and 21 of the Internal Revenue Code of 1986 and regulations pertaining to those chapters; 15 Article 2(4) provides that the Agreement also applies "to future laws which amend or supplement the laws specified in paragraph 1 of this Article". 16 It is (and has been) common ground between the parties that the laws of the United States for the purposes of the present case were relevantly Title II of the Social Security Act of the United States and associated regulations, save for those provisions excluded by Article 2(1) of the Agreement (the US Social Security Laws): PJ at [11]. It has also been and remains common ground that, under US Social Security Laws, Mr Vader has not personally been credited with any quarters of coverage: ibid. Accordingly, Mr Vader does not fall within the first limb of the Article 1(1)(i) definition, being that a person has accumulated a "period credited as a quarter of coverage under the laws of the United States". 17 Secondly, Mr Vader contended before the Tribunal, the primary judge, and on appeal that he falls within the second limb to Article 1(1)(i), namely, that he has an "equivalent period that may be used to establish the right to a benefit" under the US Social Security Laws. As put on appeal, Mr Vader contends that under US Social Security Laws, a person may qualify for a derivative entitlement based on their parents' accumulated quarters of coverage. Mr Vader contends that he has a derivative entitlement through his father and that his father's accumulation of quarters of coverage is therefore a qualifying equivalent period which may be used to establish his right to a benefit for the purposes of the second limb to Article 1(1)(i). This approach reflects the approach adopted by the primary judge to the issue. 18 Thirdly, the Tribunal found that Mr Vader's father had, under US Social Security Laws, accrued over forty quarters of coverage, and was thereby entitled to benefits under US Social Security Laws: at [68]-[72] of the Tribunal's reasoning. The primary judge appears to have accepted that finding: PJ at [59]-[70]. 19 Fourthly, the Secretary on appeal did not dispute that Mr Vader's father had accumulated forty quarters of coverage under US Social Security Laws: Transcript p. 8. Likewise, the Secretary accepted that, under US Social Security Laws, a person such as Mr Vader may qualify to be paid a derivative benefit based on their parent accumulating certain quarters of coverage: Appellant's Submission (AS) at [30]. However, even on that view, the Secretary submits that Mr Vader has not accumulated an "equivalent period that may be used to establish the right to a benefit". The Secretary's submissions as put on the appeal can be summarised as follows. (1) A person can be credited with a quarter of coverage under US Social Security Laws and thereby satisfy the first limb of Article 1(1)(i) only where they have paid a monetary contribution into a social benefits fund: Appellant's Further Submissions (AFS) at [3], [5]. (2) Under US Social Security Laws, there are certain categories of persons - namely certain veterans and individuals interned during World War Two - who did not make monetary contributions into a social benefits fund, but are deemed (for the purposes of determining entitlements) to have paid wages into the social benefits fund: AFS at [4]. In that context, an "equivalent period" in the second limb of Article 1(1)(i) means an equivalent earnings-based contribution which is, therefore, apt to describe those persons who are deemed to have contributed to a social benefits fund: AS at [36]. (3) Persons in Mr Vader's circumstances, however, who have made no actual or deemed contributions to the social benefits fund but receive benefits which are derivative of their relationship to another person are not credited with an "equivalent period that may be used to establish the right to a benefit under United States law" and therefore do not fall within the first or second limb of Article 1(1)(i).

2.2 The decisions of the Tribunal and the primary judge 20 The Tribunal, as noted above, determined that Mr Vader was eligible for the pension. In summary, the Tribunal: (1) accepted that Mr Vader's father is entitled to United States social security benefits of a relevant kind and has accrued over forty quarters of coverage: at [53] and [68]-[72]; (2) found that, under United States law, Mr Vader was a disabled child of a person who was eligible for benefits under United States law: at 72; (3) referred to material, the effect of which was that the dependent of a worker who has earned coverage under US Social Security Laws may receive derivative benefits under those laws, and concluded that Mr Vader was therefore eligible for a benefit under US Social Security Laws: at [73] and [84]; and (4) found that a benefit of that kind - namely, a benefit accruing to Mr Vader by virtue of his father's period of coverage - is an "equivalent period that may be used to establish the right to a benefit under the laws of the United States": at [85]. 21 Two further aspects of the Tribunal decision should be noted. First, in the course of its reasons, the Tribunal referred to certain documents relating to the content of US Social Security Laws. These included an extract from evidence in Burnside and Secretary, Department of Families, Community Services and Indigenous Affairs [2006] AATA 1048 upon which the Secretary relied here in submitting that the decision in Burnside should be followed: Tribunal at [57], [60]-[63] and [73]. That evidence was reproduced in Part C of the Appendix to the Tribunal's reasons in Burnside. In this regard, I note that the Tribunal is not bound by rules of evidence, although the rules of evidence can serve as a (oft-times valuable) guide in administrative tribunal decision-making: Sullivan v Civil Aviation Safety Authority [2014] FCAFC 93; (2014) 226 FCR 555 at [93]-[97] (Flick and Perry JJ). 22 In addition, the Secretary filed submissions in the Tribunal which attached email correspondence between persons in Australia and persons working in the United States Social Security Administration. In that correspondence, the Australian Government asked the United States Social Security Administration to answer certain questions concerning Article 1(1)(i). In response, various individuals from the States Social Security Administration proffered opinions on the questions as to the operation and effect of US Social Security Laws, including with respect to a person in Mr Vader's circumstances (the Article 1(1)(i) opinion). However, it appears that the employees communicating with the Australian Government were not the persons who had provided the opinions. For example, one of the emails is apparently from an employee who expresses various opinions for the Director of the "Office of Data Exchange and International Agreements". Another exchange dated 14 January 2022 from an employee at the Office of Data Exchange, Policy Publications, and International Negotiations, for example, reads that: We are still working to obtain answers to your questions. Your questions have passed through our legal department and are now with our policy staff. We want to make sure we provide the most comprehensive response we can. We hope to respond to your questions by next week. (Emphasis added.) 23 Furthermore, the email correspondence provides neither the identity, nor the qualifications and expertise, of the individuals within the United States Social Security Administration "legal department" and the "policy staff" who were apparently consulted; nor was other evidence led as to their identity and expertise to express the opinions contained in the email correspondence. 24 Secondly, the primary judge's reasoning departed from that adopted by the Tribunal. In post-‍hearing submissions, the parties responded to a question from the Full Court as to whether they sought to uphold any part of the Tribunal's reasoning concerning Article 1(1)(i) of the Agreement. Both parties confirmed that they did not. 25 The Secretary appealed the Tribunal's decision under s 44 of the AAT Act. The relevant particulars of the first ground of appeal before the primary judge were as follows: a. The Tribunal erred in its interpretation of the provisions dealing with a "United States period of coverage" in Article 1(1)(i) and Article 9(1) of the US Agreement by concluding that the question of whether a child had a "United States period of coverage" could be determined by reference to whether the person's parent had quarters of coverage that could potentially meet that requirement: [85]. It found, (erroneously) that because the Respondent's father, who resides in the United States and is (or at least was in October 2017) in receipt of Veterans' Administration benefits, might potentially have been eligible for Social Security Disability Insurance (SSDI) benefits, the Respondent met the requirement of having a "United States period of coverage" and thus could avail himself of the terms of Article 9(1) of the US Agreement to meet the residence requirement for DSP: [85] (and see also apparent reliance on Article 3 at [78]). b. The Tribunal erroneously relied on laws other than those exhaustively identified in Article 2(1)(a) of the US Agreement, i.e., those governing the "Federal old-age, survivors, and disability insurance programs", to find that the Respondent had a relevant United States period of coverage (relevantly, "quarters of coverage"), by relying, among other things, on his potential or hypothetical eligibility - in the United States - for a "needs-based SSI [Supplemental Security Income] benefit" (see reasons at [63]) and see also reasons at [39]-[43]; [73]. c. The Tribunal misinterpreted the term "or any equivalent period that may be used to establish the right to a benefit under the laws of the United States" in Article 1(1)(i) of the US Agreement and interpreted the word "benefit" as having some broad operation beyond the manner in which that term was defined in the US Agreement: see reasons at [80]; [85]. (Emphasis in original.) 26 The primary judge relevantly accepted that grounds (b) and (c) above were made out: at [58]. In this respect, the primary judge held that the Tribunal had wrongly focused on whether Mr Vader is entitled to a "benefit" under US Social Security Laws, whereas the Agreement is "concerned with the accumulation of periods in order to qualify for a benefit": at [51] (emphasis added). The primary judge thus held (at [52]-[53]): Therefore, to the extent that the Tribunal reasoned from a view about whether Mr Vader was entitled to a benefit under the US Social Security Laws for the purposes of reaching a conclusion as to the application of Art 9 of the Agreement, that reasoning involved an error of law. It follows that the reasons of the Tribunal depend, to that extent, upon an incorrect view as to the meaning of the Agreement because a period in which a person who is a child may have qualified to receive a benefit under US Social Security Law could not be a United States period of coverage. (Emphasis added.) 27 Nonetheless the primary judge did not accept that the Tribunal's ultimate conclusion was incorrect and that its decision should be set aside. Rather, the primary judge held that the "qualifying period that applied to Mr Vader (namely, quarters of coverage on the part of a parent) was 'an equivalent period that may be used to establish the right to a benefit under the laws of the United States'": at [61]. The primary judge's reasons for so holding were explained at [63] as follows: … in relation to the United States, benefit includes a benefit for which provision is made in the laws of the United States. The child insurance benefit under the US Social Security Laws is such a benefit. The qualifying period that may be used to establish the right of a child to such a benefit is a period of quarters of coverage of the child's parent. Therefore, for a minor child, it is a qualifying equivalent period. That is not to say that the minor child is claiming that the parent's quarters of coverage apply to the child. Rather, it is to say that the way a child qualifies is by the parent's quarters of coverage. 28 That being so, the primary judge held that particular (a) of the first ground of appeal was not made out, and the Tribunal's decision should be upheld despite the error in its reasoning. 29 Two further comments should be made about the primary judge's decision. First, the primary judge's reasons do not identify with specificity the documents which were in evidence before his Honour. However, it appears that the text of certain provisions of Title II was in evidence before the primary judge, as well as an affidavit of Mr Jonathon Papalia, lawyer at the Australian Government Solicitor, sworn on 21 March 2023. That affidavit was made "for the proposes of providing to the Court documents which were received by [the] Tribunal but which do not form part of the Appeal Book". Annexed to Mr Papalia's affidavit was a copy of the Secretary's submissions in the Tribunal, including the email correspondence containing opinions provided by United States Social Security Administration staff. The primary judge did not refer to the opinions in his Honour's reasons for judgment. 30 Secondly, the primary judge decided the s 44 appeal on a basis which did not necessarily reflect the way in which the parties put their respective cases. However, the Secretary expressly disavowed any challenge to the decision under appeal on the grounds of any denial of procedural fairness: AFS at [14]. That issue can therefore be put to one side.

3.1 The issues raised by the absence of expert evidence as to the content of US Social Security Laws 31 The Secretary's sole ground of appeal is that the primary judge erred in finding that Mr Vader had accumulated a United States period of coverage as defined in Article 1(1)(i). The reasons for advancing that submission are described earlier at [19] above. In essence, Mr Vader contends that the primary judge's decision was correct for the reasons given by his Honour. 32 Given that Article 1(1)(i) directs attention to the laws of the United States, the parties' submissions focused on their different constructions of US Social Security Laws and, in particular, Title II of the Social Security Act (42 U.S.C. 417). 33 Notwithstanding that it was common ground that the construction of Article 1(1)(i) turned on the proper construction of US Social Security Laws, it became apparent on the second (and final) day of the hearing of the appeal that neither party had led expert evidence as to the content of US Social Security Laws before the Tribunal or the primary judge. In those circumstances, the Court invited the parties to file post-hearing submissions with respect to (relevantly) the following question: (3) In circumstances where: (a) the parties are agreed that the proper construction of the definition depends on the meaning of Title II of the Social Security Act; (b) the parties are in issue as to the meaning of Title II; (c) no expert evidence has been led on the meaning of Title II; and (d) the appellant does not raise any complaint of a breach of procedural fairness by the primary judge in adopting a construction for which neither party contended; on what basis can the appellant establish that the primary judge fell into error? (Emphasis in the original.) 34 In their post-hearing submissions in answer to this and other questions, the parties each acknowledged that there was no expert evidence concerning the content of foreign law: AFS at [6]; respondent's submissions addressing the questions posed by the Court on 21 November 2023 (RFS) at [16]. That acknowledgment was plainly correct. First, the evidence attached to the Tribunal's decision in Burnside - to which reference was occasionally made by the parties in the appeal - was not the evidence of an expert witness in this proceeding. Likewise, it could not be said that the opinions apparently given by employees of the United States Social Security Administration constituted expert evidence. Without intending any disrespect to those persons, that evidence was opinion evidence which was not admissible to prove the content of United States law, being the relevant fact in issue: s 76(1) of the Evidence Act 1995 (Cth). Among other difficulties, there was simply no evidence that the person or persons expressing the opinions in question had "specialised knowledge based on the person's training study or experience" so as to meet the expert evidence exception in s 79(1) of the Evidence Act to the opinion evidence rule in s 76(1): see e.g. Dasreef Pty Ltd v Hawchar [2011] HCA 21; (2011) 243 CLR 588 at [32] (French CJ, Gummow, Hayne, Heydon, Crennan, Kiefel and Bell JJ). 35 In oral reply submissions, counsel for the appellant referred to a United States case which was said to support their construction of Article 1(1)(i). A copy of a reported version of that case was emailed to the Court after the hearing. While s 175(2) of the Evidence Act provides that "[e]vidence of the interpretation of a statute of a foreign country may be adduced by producing a book containing reports of judgments of courts of the country if the book is or would be used in the courts of the country to inform the courts about the interpretation of the statute", with respect, however, that case in isolation did not address the lacuna in the appellant's evidence here. Quite apart from the fact that Mr Vader did not have any opportunity to make submissions about the relevance or status of the US decision, the decision alone is no substitute for expert evidence in the circumstances of the present case. For example, there was no evidence or agreement as to whether or not the decision represented the present state of the law in the United States. 36 Both parties however submitted in post-hearing submissions that the absence of expert evidence as to the content of United States law was not an impediment to the Full Court construing Article 1(1)(i) and determining whether, on the basis of that construction, the primary judge fell into error. Rather, the parties submitted that the constructional dispute could be resolved by applying Australian principles of statutory construction to construe the text of Title II (the hybrid approach). In support of this hybrid approach, the parties submitted that: (1) even though there is no expert evidence before the Court, the text of the relevant United States law, being Title II, is in evidence (AFS at [6]; RFS at [16]); (2) in the absence of expert evidence about foreign law, it is presumed that Australian law will apply (AFS at [7]; RFS at [17]); (3) applying that presumption, the Court should construe the text of Title II as if it was construing an Australian law (AFS at [7]), that is, "when construing Title II, this Court ought to apply ordinary principles of statutory interpretation under Australian law" (RFS at [17]); and (4) the Court can then construe Article 1(1)(i) of the Agreement based upon its construction of Title II by applying this hybrid approach: ibid. 37 In the alternative, if the Court did not consider it appropriate to apply this presumption, the Secretary submitted the Full Court should grant leave for the Secretary to lead further evidence on the appeal under s 27 of the Federal Court of Australia Act 1976 (Cth) (FCA Act) (AFS at [8]), as opposed to remitting the matter to the primary judge (AFS at [14]). Nor did Mr Vader contend that the matter should be remitted. Rather, Mr Vader submitted that "[t]o the extent that the Appellant's construction needs the Court to go beyond the text of Title II, and requires expert evidence to bear it out, the appeal must fail in the absence of such expert evidence": RFS at [20]. Alternatively, if the Court were minded to grant leave to the Secretary to adduce further evidence, Mr Vader contended that he should be afforded the opportunity to obtain responsive expert evidence, the costs of which should be covered by the Secretary irrespective of the outcome of the appeal: RFS at [21]. In this regard, as I have earlier explained, neither party contended that there had been any breach of procedural fairness by the primary judge for which remittal would have been the logical outcome (as submitted by the Secretary).

3.2 Rejection of the parties' proposed hybrid approach to determining the content of US Social Security Laws to address the lack of any expert evidence 38 I agree that the definition of "United States period of coverage" in Article 1(1)(i) (and enacted domestically) was intended to pick up periods of coverage credited as a quarter of coverage "under United States law" in accordance with the ordinary meaning of those words. This is confirmed by the definition of "laws" (quoted above) which, as regards the United States, are defined as "the laws governing the Federal old-age, survivors, and disability insurance program", referring specifically, among other laws, to Title II: Article 2(1)(a). 39 With respect to the principles applying to the construction of the text of a treaty incorporated into Australian law, I explained in Tech Mahindra Ltd v Commissioner of Taxation [2015] FCA 1082; (2015) 101 ATR 755 at [51] that: Ordinary principles of statutory construction apply to the interpretation of an international convention enacted into domestic law: Minister for Home Affairs of the Commonwealth v Zentai [2012] HCA 28; (2012) 246 CLR 213 (Zentai) at 238 [65] (Gummow, Crennan, Kiefel and Bell JJ); Maloney v The Queen [2013] HCA 28; (2013) 252 CLR 168 (Maloney) at 221-222 [134] (Crennan J) and 234-235 [174] (Kiefel J). It does not follow, however, that principles of treaty interpretation have no bearing on the issue of statutory construction. Rather, where, as here, the exact text of a treaty has been given effect by domestic law, Parliament's adoption of the treaty text shows its objective intention to fulfil its international obligations. It is therefore appropriate to construe that text for domestic purposes having regard to ordinary principles governing the interpretation of treaties: Federal Commissioner of Taxation v SNF (Australia) Pty Ltd [2011] FCAFC 74; (2011) 193 FCR 149 (FCT v SNF) at 186 [119] (the Court). Understood in this way, the application of international principles of treaty construction to a law enacting a treaty gives effect to the requirement in s 15AA of the Acts Interpretation Act 1901 (Cth) (the Interpretation Act) to prefer the interpretation that best achieves the object or purpose of the Act over each other interpretation. As, for example, Bell J reasoned in Maloney at 255-256 [235] with respect to the transposition of the definition of 'special measures' in Article 1(4) of the International Convention on the Elimination of All Forms of Racial Discrimination into s 8(1) of the Racial Discrimination Act 1975 (Cth): The legislative intention to be discerned is that the expression 'special measures' in s 8(1) bear the same meaning as in the treaty. That meaning is ascertained by reference to the ordinary meaning of the words in their context and in the light of the object and purpose of the Convention, and by reference to the materials comprising context and referred to in Art 31(2) and (3) of the Vienna Convention. (Cited with approval by the High Court in Addy v Federal Commissioner of Taxation [2021] HCA 34; (2021) 273 CLR 613 at [23].) 40 In this respect, Article 31(1) of the Vienna Convention on the Law of Treaties, opened for signature 23 May 1969, 1155 UNTS 331, [1974] ATS 2 (the Vienna Convention) articulates a general rule of interpretation that "[a] treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose." As such, treaty interpretation is approached in a holistic manner requiring a consideration of text, object and purpose: Applicant A v Minister for Immigration and Ethnic Affairs (1997) 190 CLR 225 at 231 (Brennan CJ) and 254-256 (McHugh J); Task Technology Pty Ltd v Federal Commissioner of Taxation [2014] FCAFC 113; (2014) 224 FCR 355 at [12]. In the present case, the plain text of the treaty itself reveals its object and purpose, and it was not suggested by either party that any extrinsic materials or reliance on supplementary means of interpretation would suggest any different meaning. 41 That being so, the first issue is whether the Secretary can establish error in the primary judge's decision in circumstances where there is a dispute as to the proper construction of US Social Security Laws but without expert evidence as to the content of those laws. This issue arises, as I have mentioned, in a unique context because the reference to United States laws occurs in the text of an international agreement which the Australian Parliament has incorporated verbatim into domestic law by the enactment of the International Agreements Act. At the risk of oversimplification, another way in which the issue might be put is that, in essence, the Court is asked to construe an Australian statute which incorporates concepts existing under foreign law via the enactment of an international treaty. No party directed the Court's attention to any consideration in the cases of an analogous issue. 42 With respect, the parties' hybrid approach - by which Article 1(1)(i) could be construed absent expert evidence by reference to Australian principles of statutory construction - cannot be accepted. Properly understood, Article 1(1)(i) (as incorporated into domestic law by s 6(1) of the International Agreements Act) falls to be interpreted based upon how US Social Security Laws have been or would be interpreted under United States law. In the absence of expert evidence as to the content of US Social Security Laws, Mr Vader correctly contends (in his alternative position) that the appellant has not, therefore, established that the construction of Article 1(1)(i) adopted by the primary judge was incorrect. 43 To understand why I have reached this view, it is necessary to explain certain principles concerning proof of foreign law. 44 First, as earlier explained, it is well-established that "courts of Australia are not presumed to have any knowledge of foreign law": Neilson at [115] (Gummow and Hayne JJ). Hence, "foreign law is a question of fact to be proved by expert evidence": ibid. However, in FS Cairo (Nile Plaza) LLC v Brownlie [2021] UKSC 45, [2022] AC 995 at [148] Lord Leggatt (with whose reasons Lord Reed, Lord Lloyd-‍Jones, Lord Briggs and Lord Burrows relevantly agreed) observed in obiter that: The old notion that foreign legal materials can only ever be brought before the court as part of the evidence of an expert witness is outdated. Whether the court will require evidence from an expert witness should depend on the nature of the issue and of the relevant foreign law. In an age when so much information is readily available through the internet, there may be no need to consult a foreign lawyer in order to find the text of a relevant foreign law. On some occasions the text may require skilled exegesis of a kind which only a lawyer expert in the foreign system of law can provide. But in other cases it may be sufficient to know what the text says. If, for example, the question is whether a spouse has a right to claim damages for bereavement under the applicable foreign law, producing a copy of the relevant foreign legislation (with, if necessary, an English translation) is a much more secure basis for a finding than presuming that the foreign law is the same as the English law. 45 Similarly, under Australian law, in some cases where the text of the foreign statute is sufficiently clear and precise, it may suffice to tender the statute pursuant to s 174(1) of the Evidence Act which permits such evidence to be adduced: Heydon, Cross on Evidence (14th Ed) (LexisNexis, 2024) at p. 1622. However, this is plainly not a case where it is sufficient to know what the text says. The parties have adopted tenable but diametrically opposite views as to the proper construction of US Social Security Laws based upon the text of those laws, including as to the very nature of the system established by Title II. Thus, while the Secretary contended that Title II is solely a "contributions-based" system, that was denied by Mr Vader: AFS at [3]; RFS at [9]-‍[11]. 46 Secondly, it is well-established that, absent proof of foreign law, it is presumed that foreign law corresponds with, and is the same as, the law of the forum: Neilson at [116]; Damberg v Damberg [2001] NSWCA 87; (2001) 52 NSWLR 492 at [118] Heydon JA (Spigelman CJ and Sheller JA agreeing); see also the extensive discussion of the presumption and its limitations in Brownlie at [108]-[112] and [119]-[149] (Lord Leggatt, with whose reasons Lord Reed, Lord Lloyd-Jones, Lord Briggs and Lord Burrows agreed on the foreign law issue). However, the presumption is not universally applied, with there being many examples where courts have refused to apply the presumption: Damberg at [120]-[140] (referring to authorities in Australia, England, Canada and South Africa). Generally speaking, the presumption has been applied in cases where it was reasonable to apply the law of the forum because it was unlikely to differ greatly from the foreign law: Damberg at [144]. However, as Heydon JA concluded in Damberg at [160]: In short, the courts are averse to pronouncing judgments on hypotheses which are not correct. To do so is tantamount to giving advisory opinions and to encouraging collusive litigation. On the other hand, the courts will act on admissions of or agreements about matters of fact where there is no reason to doubt their correctness. But they are reluctant to do so where there is reason to question the correctness of the facts admitted or agreed. A similar caution appears to apply in relation to an assumption or agreement that foreign law is the same as the lex fori. 47 Thirdly, the presumption has also been applied in some cases where the text of foreign law is in evidence, but no expert evidence has been adduced as to its proper construction or where the expert evidence is deficient. In such cases, the presumption is that principles of statutory construction under the foreign law are the same as Australian principles of statutory construction. Hence, in Neilson at [125], Gummow and Hayne JJ held that: If there is thought to be some deficiency in the evidence, the "presumption" that foreign law is the same as the law of the forum comes into play. That would then require an Australian court to approach the task of construing [the text of the foreign law] as it would approach the construction of an Australian statute. Neither the absence of pleading the relevant content of foreign law nor the absence of proof would be fatal to the case of the party relying on the relevant provision of foreign law. (Emphasis added; citations omitted.) 48 Examples where this approach to the construction of the text of foreign statutes have been adopted include Blackmores Limited, in the matter of Blackmores Limited [2023] FCA 624 at [20] (Jackman J) and Lee v Minister for Home Affairs [2020] FCA 487 (Rangiah J). That presumption also appears to broadly mirror the approach traditionally adopted in the United Kingdom, where it has also long been accepted that foreign law is a question of fact to be proved in evidence: see, eg, Di Sora v Phillipps (1863) 10 HL Cas 624; 11 ER 1168 at 1170; F & K Jabbour v Custodian of Israeli Absentee Property [1954] 1 WLR 139 at 148, where Pearson J construed the text of certain Israeli laws without the assistance of an expert, and "assumed that the Israeli rules of construction are the same as the English rules of construction". Further there is authority to the effect that the presumption will be used only against, and not in favour of, the party having the burden of proving the content of the foreign law: see Neilson at [37] (McHugh J (diss)); and BP Exploration Co (Libya) Ltd v Hunt [1980] 1 NSWLR 496; [1980] 1 NSWLR 496 at [26] (Hunt J). 49 The authorities thus establish that, in certain circumstances, common law rules will permit a Court to construe the text of a foreign statute according to domestic principles of construction. However, that principle does not, in my view, assist in the present case. That is so for four reasons. 50 First, for the Court to embark upon construing the text of foreign law using Australian principles of construction will often invite error in the understanding of foreign law. Thus, Gummow and Hayne JJ in Neilson observed at [115] that: [A]n English translation of the text of foreign written law is not necessarily to be construed as if it were an Australian statute. Not only is there the difficulty presented by translation of the original text, different rules of construction may be used in that jurisdiction. (Emphasis added.) 51 Not only is there good reason to be cautious about assuming that Australian principles of statutory construction mirror those in the United States but, in the present case it is highly likely that there is a body of existing caselaw in the United States which has in fact construed US Social Security Laws. Accordingly, even if US principles of statutory construction were applied by this Court, there is a serious risk that the Court may adopt a construction of the foreign law which departs from that adopted in the United States. That risk is amplified if Australian principles of statutory construction are applied. 52 Secondly, the issue of foreign law in this case arises in a different context from cases such as Neilson in which an appellant sought damages for an injury sustained abroad: Neilson at [2] (Gleeson CJ). In those circumstances, applicable principles of private international law directed the Court to apply the lex loci delicti, being the law of the place in which the injury occurred: at [11]. Findings of fact as to the content of foreign law in this context are pure findings of fact. As such, they have significance only as between the parties and "create no precedent": Neilson at [115]. 53 However, in this case, and as the parties have repeatedly emphasised, any findings of fact with respect to the proper construction of US Social Security Laws would have significance beyond the parties to this case. This is because they would form the basis on which a domestic statute (i.e. Article 1(1)(i) as enacted by the International Agreements Act) is construed. As such, the findings would not merely be findings of fact, but also of law. Significantly, as French CJ has observed, the construction of a statute impacts not just the parties to litigation, but also "those who are required to apply or administer the law, those who are to be bound by it and those who advise upon it generally": International Finance Trust Company Limited v New South Wales Crime Commission [2009] HCA 49; (2009) 240 CLR 319 at [42] (French CJ). The difficulty in the present case is that the Secretary is effectively, with respect, asking the Court to construe an Australian statute, which is intended to incorporate concepts of US Social Security Laws via the enactment of the Agreement, on a knowingly incomplete and therefore potentially erroneous understanding of those concepts because of the failure to lead expert evidence as to their content under US Social Security Laws. That potentially erroneous construction would then not only affect the parties to this litigation but is one which those required to administer the law would no doubt apply (to the detriment potentially, if the Secretary's construction were accepted in this case, of a highly vulnerable class of individuals in the context of this particular legislation). 54 Thirdly, as earlier held, the phrase "under United States law" should be construed in accordance with its ordinary meaning and therefore under United States law as interpreted and applied in the United States. That intention is confirmed by Article 2(1)(a) and by the distinction drawn throughout the Agreement between the laws of the United States and the laws of Australia: see e.g. Articles 3, 4, and 5. There is nothing in the text of the International Agreements Act, including the Agreement in Schedule 13 of that Act, which suggests that that phrase could be construed as a reference to United States law as construed in accordance with Australian principles of statutory construction; nor was any submission made that that was the correct construction of Article 1(1)(i) of the Agreement, applying relevant principles of treaty interpretation. It would be wrong, therefore, in my view to import an intention to Parliament that Article 1(1)(i) could be construed otherwise than in accordance with United States caselaw or (in the absence of an established meaning through the caselaw) through the application of United States principles of construction. That would undermine the State parties' apparent intention under the Agreement and therefore the intention of the Parliament in implementing Australia's obligations under that Agreement by giving it legal force and effect under Australian law. 55 This approach receives some support from the decision of Gleeson J in Liaoning Zhongwang Group Co Ltd v Alfield Group Pty Ltd [2017] FCA 1223. In that case, the respondent resisted the enforcement of a Chinese arbitral award relying, among other things, on s 8(5)(b) of the International Arbitration Act 1974 (Cth). That section relevantly raised the question of whether the arbitration agreement was not valid "under the law of the country where the award was made" being, in that case, China. The respondent sought to rely on the presumption that Chinese law is the same as Australian law (similar to the approach in Hua Wang Bank Berhad v Commissioner of Taxation [2014] FCA 1392; (2014) 100 ATR 244): at [77]. However, the applicant submitted that the presumption had no application because the section identified, "as a particular circumstance in which the court will depart from the norm of ready enforcement of foreign awards, the circumstance that the arbitration agreement is invalid according to Chinese law on the facts of this case": at [94]. Justice Gleeson found at [96]-‍[97]: I am not persuaded that the question of the validity of an arbitration agreement is an area of broad legal principle upon which it is reasonable to assume that the laws of Australia and the laws of China are broadly the same. Tweeddale A and Tweeddale K, Arbitration of Commercial Disputes: International and English Law and Practice (Oxford University Press, 2007), para [7.01], express the view that perhaps no other area of arbitration law has received as much academic interest as the issue of which law or laws govern the arbitration agreement and the arbitration procedure. Application of the presumption in this context may undermine the legislative framework which is expressed, in several places, to apply by reference to the law of the country in which the arbitration took place, or the law of the country in which the award was made. It would be potentially at odds with the importance of attempting to "create or maintain, as far as the language employed by Parliament in the [Act] permits, a degree of international harmony and concordance of approach to international commercial arbitration": cf TCL Air Conditioner (Zhongshan) Co Ltd v Castel Electronics Pty Ltd [2014] FCAFC 83; (2014) 232 FCR 361 (TCL) at [75]. Further, in my view, the proper interpretation of s 8(5)(b) is that the requirement for proof of the circumstance that the arbitration agreement is not valid under the law of the country where the award was made is a requirement for affirmative proof of the foreign law by the party seeking to invoke s 8(5)(b). That requirement is not met by applying Australian law in the absence of proof of the foreign law. This interpretation is based primarily on the language which requires that the party resisting enforcement "proves to the satisfaction of the court" invalidity "under the law of the country where the award was made" without reference to any presumption about the content of that law. A contrary interpretation would place the burden upon the party seeking to enforce the award that the laws of the country in which the award was made was different from the laws of Australia, which is inconsistent with the general scheme of facilitating enforcement of foreign awards subject to limited circumstances which may be demonstrated by a party resisting enforcement. (Emphasis added.) 56 Thus in common with the approach which I have adopted, her Honour considered, through the prism of legislative intention, whether proof of foreign law was required in the case of an Australian statute requiring an issue to be determined by reference to foreign law. 57 The decision in BP Exploration also lends support to the approach which I have adopted. No evidence was led in that case as to whether service by registered post was in accordance with the laws of Texas. However, orders had been made at first instance relevantly dispensing with personal service on Mr Hunt and ordering that service of the proceeding be deemed to have occurred on him in Texas ten days after being posted from Australia. In setting aside those orders, Hunt J considered that the presumption that foreign law was the same as (relevantly) the law in New South Wales "is intended to operate against, not in favour of, the party whose obligation it is to prove the foreign law, so that he is deprived of the benefit of a right or exemption given by that foreign law, but not by [in that case] New South Wales law, if he does not establish that foreign law in the proper way": at [26] (Hunt J). Furthermore and significantly for present purposes, his Honour then found (at [26]) that: It would, in my opinion, be an absurd interpretation of the requirements of Pt 10, r 5 [of the Supreme Court Rules 1970] (that non-personal service be in accordance with the law of the country in which service is to be effected) which enabled a judgment creditor, by mere non-disclosure on the ex parte application for registration, to obtain the benefit of a more advantageous New South Wales provision as to service, which is in fact not available in the foreign jurisdiction in which service is to be effected. Such an interpretation would render the requirement in r 5 otiose. (I interpose that, as those proceedings concerned the registration of a foreign judgment in New South Wales, these findings were made in the alternative to his Honour's conclusion that Parts 9 and 10 of the Supreme Court Rules 1970 (NSW) were irrelevant to proceedings under the Foreign Judgments (Reciprocal Enforcement) Act 1973 (NSW).) 58 Finally, I have identified two decisions which might be thought to point to a different approach from that which I have adopted but which I consider are distinguishable, namely: Berhad; and ET-china.com International Holdings Ltd v Cheung [2019] NSWSC 1874; (2019) 142 ACSR 121. 59 In Berhad, a question arose about whether the appellants were "entitled to invoke any of three double taxation treaties between Australia and those nations": at 3. The relevant taxation treaties were given "the force of law according to its tenor" pursuant to s 5 of the International Tax Agreements Act 1953 (Cth). In turn, in determining whether double taxation would arise, a question arose as to the content of United Kingdom and Swiss taxation law. However, the parties had not led any evidence on this issue: at [423]. In those circumstances, Perram J proceeded "on the basis that the law of the United Kingdom is the same as Australian law": at [423]. Based on this approach, his Honour found that there was no double taxation: at [429]-[440]. This case is distinguishable to Berhad as the foreign statute is before the Court here. Nor was the issue of whether such an approach accorded with Parliament's intention in enacting the treaties in question considered in the judgment or apparently addressed in argument by the parties in Berhad. 60 In Cheung, there was a question as to the law which applied in relation to the plaintiff's claim against some of the defendants: at [54]. Section 7 of the Foreign Corporations (Application of Laws) Act 1989 (Cth) provides that any questions relating to "the rights and liabilities of the members or officers of a foreign corporation" in relation to a corporation "is to be determined by reference to the law applied by the people in the place in which the foreign corporation was incorporated." Justice Stevenson found that the "law to be applied is the law of Jersey": at [57]. Pursuant to s 174 of the Evidence Act 1995 (NSW), the Court received a copy of the relevant section of the Jersey statute. Relevantly, Stevenson J found at [60]-[63]: In the absence of evidence of a foreign law, I must presume that the applicable law is the same as the lex fori: Neilson v Overseas Projects Corporation of Victoria Ltd (2005) 223 CLR 331; [2005] HCA 54 at [125] (Gummow and Hayne JJ). No party suggested that the Australian law concerning the duties of directors was, in substance, different from that set out in Art 74(1) of the Jersey legislation. Argument before me as to Mr Marcou's and Mr Rose's duties proceeded upon the basis that Jersey law was the same as that of Australia. Argument thus proceeded by reference to Australian authorities. It was common ground that the law applicable to the determination of ETCI's accessorial liability claims was to be determined in accordance with the lex fori; that is the law of Australia. 61 Therefore, in Cheung, the New South Wales Supreme Court adopted the hybrid approach proposed by the parties in this proceeding. However, three points can be made briefly distinguishing this decision. First, issues as to the appropriateness of this approach in the context of considering a statute do not appear to have been agitated in Cheung. Secondly, the substantive content of the foreign law in Cheung was apparently similar to Australian law. By contrast, this case concerns a US legislative scheme which is plainly different on its face from the Australian legislative scheme. Thirdly, while in Cheung there was a contest about the application of the law to the facts of the proceeding, it was not the case that the parties relied upon opposing and apparently tenable interpretations of the foreign statute. Accordingly, I do not consider that Cheung should guide the Court's consideration in this case.

4.1 Principles as to the Court's power to determine an appeal 62 For the reasons set out above, on appeal, the Full Court must construe Article 1(1)(i) according to United States law, as interpreted by United States Courts or, in the absence of such evidence, by applying United States principles of construction. In the absence of the expert evidence necessary to make those findings, the appeal should be dismissed. That is because, irrespective of his Honour's reasoning, the Secretary has failed to establish that the construction adopted by the primary judge is in error. To explain that conclusion, it is necessary to outline certain fundamental principles concerning the Court's power to hear and determine an appeal. 63 This is an appeal by way of rehearing. As Gageler J (as his Honour then was) explained in Minister for Immigration and Border Protection v SZVFW [2018] HCA 30; (2018) 264 CLR 541 at [30]: the appellate court is permitted and, unless the appellate court dismisses the appeal or remits the matter for rehearing, required to "give the judgment which in its opinion ought to have been given in the first instance". (Citations omitted). 64 However, and as his Honour continued, an appeal by way of rehearing is a procedure for the correction of error. Hence, his Honour observed that "the existence of an error, whether of law or fact, on the part of the court at first instance is an indispensable condition of a successful appeal" (emphasis added): quoting Norbis v Norbis [1986] HCA 17; (1986) 161 CLR 513 at 519 (Mason and Deane JJ); and citing CDJ v VAJ [1998] HCA 67; (1998) 197 CLR 172 at 201-202 [111] (McHugh, Gummow and Callinan JJ); Coal and Allied Operations Pty Ltd v Australian Industrial Relations Commission [2000] HCA 47; (2000) 203 CLR 194 at 203-204 [14] (Gleeson CJ, Gaudron and Hayne JJ). Thus, to succeed on appeal, an appellant must show the existence of an error of law or fact in the Court below. Where, as on this appeal, the appellant contends that a primary judge has misconstrued a statute, the appellant will succeed only if they demonstrate an error in construing that legislation. 65 Here, the Secretary has not demonstrated that the conclusion reached by the primary judge, being that Mr Vader had accumulated a United States period of coverage, was in error. The Secretary's sole ground of appeal was that such a conclusion was not open to his Honour on the text of Article 1(1)(i), based on the content of US Social Security Laws. For reasons earlier given, expert evidence as to the content of US Social Security Laws was therefore required. Having failed to adduce any such evidence, the Secretary cannot establish that the conclusion reached by the primary judge of Article 1(1)(i) was erroneous. 66 In those circumstances and there being no complaint of any procedural unfairness, it follows that the appeal must be dismissed. 67 I would add the following caveat. This conclusion does not mean that the construction of Article 1(1)(i) adopted by the primary judge was necessarily correct. Rather, the decision of the primary judge should, with respect, be treated with caution. This is because no expert evidence was led before the primary judge as to the content of US Social Security Laws, notwithstanding that it would have been open for the parties to do so on the s 44 appeal in circumstances where the content of US Social Security Laws was not simply a question of fact, but also of law for the reasons I have earlier explained. Specifically, under s 44(7) of the AAT Act, the Federal Court on a s 44 appeal may make findings of fact which are inconsistent with findings of fact made by the Tribunal where those findings are made as a result of an error of law and may receive further evidence under s 44(8)(b) for the purposes of making such findings.

4.2 The Secretary's application to have leave to adduce fresh expert evidence 68 Finally, as I have earlier explained, in post-hearing submissions the Secretary submitted that it would be inappropriate to remit the matter for rehearing: AFS at [14]. Nor did Mr Vader submit that remittal would be appropriate. Any question of whether the matter should be remitted for rehearing can therefore be put to one side. 69 However, in post-hearing submissions, the Secretary submitted that (AFS at [8]): [I]f the Court forms the view that the [appeal] cannot be answered without the benefit of expert evidence, then the Appellant seeks leave pursuant to s 27 of the Federal Court of Australia Act 1976 (Cth)… to adduce such evidence … This should cause no prejudice to the Respondent who is now receiving [disability pension] payment … [Leave should also be granted because] the point is one of public importance. 70 No application for leave to adduce further evidence and supporting affidavit have been filed; nor has leave to re-open in order to file and serve such an application been sought. Nonetheless, it is convenient in the circumstances to treat the submission as an application by the Secretary for leave to re-open and, in the event that that leave is granted, for leave to adduce expert evidence on the appeal as to the content of US Social Security Laws. 71 Section 27 of the FCA Act provides that "[i]n an appeal, the Court shall have regard to the evidence given in the proceedings out of which the appeal arose, and has power to draw inferences of fact and, in its discretion, to receive further evidence". Importantly, however, the power to adduce fresh evidence on an appeal "should not be construed in such a way as to obliterate the distinction between original and appellate jurisdiction": Frigger v Trenfeld (No 3) [2023] FCAFC 49 at [152] (the Court). 72 The principles guiding the consideration of applications to adduce further evidence on appeal are well-settled, and are conveniently summarised in Northern Land Council v Quall (No 3) [2021] FCAFC 2 at [16] by Griffiths and White JJ as follows: (1) The discretion conferred by s 27 is unfettered, save that it must be exercised judicially and according to principle. (2) The power to receive further evidence is remedial and its primary purpose is to empower the Court to receive further evidence to ensure that proceedings do not miscarry. (3) The power is not constrained by common law rules that govern the grant of new trials on the ground of discovery of "fresh evidence". (4) The following two considerations will normally be relevant to the exercise of the discretion: (i) the further evidence is such that, had it been adduced at trial, the result would very probably have been different; and (ii) the party seeking to adduce the evidence demonstrates that it was unaware of the evidence and could not have been, with reasonable diligence, made aware of the evidence; (5) The interests of third parties and the public at large may outweigh a party's interest in the finality of litigation … (Emphasis added; see also e.g. CKT20 v Minister for Immigration, Citizenship, Migrant Services and Multicultural Affairs [2022] FCAFC 124; (2022) 294 FCR 318 at [32] (the Court); and Frigger at [152].) 73 In addition, as the Full Court explained in Frigger at [152], the power: … is to be exercised having regard to the subject matter, scope and purpose of s 27 of the FCA Act. That includes having regard to the overarching purpose of the civil practice and procedure provisions described in s 37M of the FCA Act. 74 Section 37M in turn relevantly provides that: (1) The overarching purpose of the civil practice and procedure provisions is to facilitate the just resolution of disputes: (a) according to law; and (b) as quickly, inexpensively and efficiently as possible. (2) Without limiting the generality of subsection (1), the overarching purpose includes the following objectives: (a) the just determination of all proceedings before the Court; (b) the efficient use of the judicial and administrative resources available for the purposes of the Court; (c) the efficient disposal of the Court's overall caseload; (d) the disposal of all proceedings in a timely manner; (e) the resolution of disputes at a cost that is proportionate to the importance and complexity of the matters in dispute. 75 Having regard to these principles, it is not in the interests of justice to grant the Secretary leave to re-open to adduce further evidence at this late stage of the proceedings and it would tend to undermine the distinction between appellate and original jurisdiction. 76 First, plainly the parties are significantly at issue at to the proper construction of Title II. In those circumstances, any expert evidence led by the Secretary as to the content of US Social Security Laws may well be contested by Mr Vader, who has indicated his intention to obtain expert evidence in response if leave is granted to the Secretary. Any contest as to the proper construction of US Social Security Laws would likely be resolved only through cross-‍examination, possibly of an extensive nature. Moreover, any such cross-examination would be heard not in front of one judge, but three, in circumstances where the Full Court has already heard two days of argument on the appeal. As such, were the Secretary allowed the opportunity to adduce expert evidence under s 27 of the FCA Act, this would impose delays and further expense on Mr Vader. It would also impact on the efficient use of Court resources, and delay the timely resolution of the appeal, particularly given that all three members of the Full Court bench would need to be reassembled for further hearing. 77 Secondly, the Secretary has been on notice since at least 2020 about Mr Vader's claim to have accumulated a United States period of coverage. He has had ample opportunity to obtain expert evidence in an admissible form concerning the effect of United States law. Indeed, the Secretary obtained advice from the United States Social Security Administration, albeit that that advice was not in admissible form. In those circumstances, it could not be said that the Secretary was "unaware of the evidence and could not have been, with reasonable diligence, made aware of the evidence". Further, and as outlined above, the Secretary was entitled to adduce such expert evidence before the primary judge under s 44 of the AAT Act. 78 Ultimately, the appropriate time to have led expert evidence about the content of United States law was before the primary judge. An appeal is not, absent truly exceptional circumstances, the place to adduce expert evidence and to cross-examine expert witnesses. 79 Accordingly, the Secretary's application for leave to re-open and to adduce further evidence under s 27 of the FCA Act must be dismissed.

5. CONCLUSION 80 For the reasons set out above, the appeal is dismissed. As the Secretary has not succeeded on the appeal, he should pay Mr Vader's costs as agreed or assessed. I certify that the preceding eighty (80) numbered paragraphs are a true copy of the Reasons for Judgment of the Honourable Justice Perry.

CHARLESWORTH J 81 I have had the advantage of reading in draft the reasons prepared by Perry J and the concurring reasons of Jackson J. I agree with each of them and join in the order dismissing the appeal. I certify that the preceding one (1) numbered paragraph is a true copy of the Reasons for Judgment of the Honourable Justice Charlesworth.

JACKSON J: 82 I have had the considerable advantage of reading the reasons for decision of Perry J in draft. I agree with her Honour that the appellant has omitted to prove the relevant content of United States social security laws. It follows that the appellant has failed to establish that the primary judge erred in his Honour's identification of that content, as a necessary step in construing the term 'United States period of coverage' as defined in Article 1(1)(i) of the treaty found at Schedule 13 to the Social Security (International Agreements) Act 1999 (Cth). 83 In particular I agree, for the reasons Perry J gives, that it is not open to this Court to make findings about the relevant content of United States social security laws on the presumption that the rules of statutory interpretation that apply under United States law are the same as the rules that apply under Australian law. To construe the term 'United States period of coverage' where it appears in the Act is to identify the intention of the makers of the treaty and the intention of Parliament in enacting the treaty into domestic law. It is not to be supposed that in either case, the intention was that the phrase be construed on the basis of an incorrect understanding of the content of the United States social security laws. The appellant has failed to establish by evidence (or otherwise) what the correct understanding is, and so has failed to establish that the primary judge erred. I certify that the preceding two (2) numbered paragraphs are a true copy of the Reasons for Judgment of the Honourable Justice Jackson.