Chapter VI
General Rules of Evidence
under the WTO Jurisprudence


OUTLINE

I Burden of Proof under the WTO Jurisprudence
(ⅰ) General Rules Well Established in Violation Complaints
(ⅱ) Burden of Proof in case of Invoking an Exception
(ⅲ) Special Rules Concerning Non-Violation Claims
(ⅳ) Summary and Conclusions
II Admissibility of Certain Evidences
(ⅰ) Evidence Obtained from Prior Consultations
(a) Procedural Concern: Confidentiality of Consultations
(b) Substantial Concern: Necessity or Relevance of Evidence
(ⅱ) Arguments before Domestic Investigative Authorities
(ⅲ) Arguments Submitted after the First Substantive Meeting
(a) There is a significant difference between the claims and the arguments supporting those claims.
(b)There is no provision establishing precise deadlines for the presentation of evidence.
III Panel’s Right to Seek Information
(ⅰ) A Grant of Discretionary Authority
(ⅱ) The Admissibility of Non-requested Information
(ⅲ) Summary and Conclusions
IV Adverse Inferences from Party’s Refusal to Provide Information Requested
(ⅰ) The Authority of a Panel to Request Information from a Party to the Dispute
(ⅱ) The Duty of a Member to Comply with the Request of a Panel to Provide Information
(ⅲ) The Drawing of Adverse Inferences from the Refusal of a Party to Provide Information Requested by the Panel
V Concluding Remarks

I Burden of Proof under the WTO Jurisprudence
Generally, the question of whether a member acted in accordance with the agreement hinges frequently on whether and to what extent that member must demonstrate compliance or the complaint must demonstrate a lack of compliance. It is demonstrated that the burden of proof is a procedural concept which speaks to the fair and orderly management and disposition of a dispute. This is the issue of “the ultimate burden of proof for establishing a claim or a defence”. In this respect, the Panel Report on US-Copyright Act (DS160) states, “[w]hile a duty rests on all parties to produce evidence and to cooperate in presenting evidence to the Panel, this is an issue that has to be distinguished from the question of who bears the ultimate burden of proof for establishing a claim or a defence”.1
(i) General Rules Well Established in Violation Complaints
Art. 3.8 of the DSU provides that in cases where there is an infringement of the obligations assumed under a covered agreement -- that is, in cases where a violation is established -- there is a presumption of nullification or impairment. However, the issue of burden of proof here is not what happens after a violation is established; the issue is which party must first show that there is, or is not, a violation. In this respect, a number of GATT 1947 panel reports contain language supporting the proposition that the burden of establishing a violation under Article XXIII:1(a) of the GATT 1947 was on the complaining party, i.e., it was for the complaining party to present a prima facie case of violation before a panel. This rule is taken on by the DSB.
With regard to the issue of burden of proof, the Appellate Body in US-Shirts and Blouses (DS33) rules that: “In addressing this issue, we find it difficult, indeed, to see how any system of judicial settlement could work if it incorporated the proposition that the mere assertion of a claim might amount to proof. It is, thus, hardly surprising that various international tribunals, including the International Court of Justice, have generally and consistently accepted and applied the rule that the party who asserts a fact, whether the claimant or the respondent, is responsible for providing proof thereof. Also, it is a generally-accepted canon of evidence in civil law, common law and, in fact, most jurisdictions, that the burden of proof rests upon the party, whether complaining or defending, who asserts the affirmative of a particular claim or defence. If that party adduces evidence sufficient to raise a presumption that what is claimed is true, the burden then shifts to the other party, who will fail unless it adduces sufficient evidence to rebut the presumption.” 2And this ruling is demonstrated to be well established in subsequent cases as a general rule concerning burden of proof.
For example, in Argentina-Leather (DS155), the Panel states: “The relevant rules concerning burden of proof, while not expressly provided for in the DSU, are well established in WTO jurisprudence. The general rule is set out in the Appellate Body report on United States - Measure Affecting Imports of Woven Wool Shirts and Blouses, wherein it is stated that: ‘It is a generally-accepted canon of evidence in civil law, common law and, in fact, most jurisdictions, that the burden of proof rests upon the party, whether complaining or defending, who asserts the affirmative of a particular claim or defence. If that party adduces evidence sufficient to raise a presumption that what is claimed is true, the burden then shifts to the other party, who will fail unless it adduces sufficient evidence to rebut the presumption’.” 3
And in US-Cotton Yarn (DS192), the Panel rules in pertinent part: “The Appellate Body and subsequent panels endorsed this principle that a complainant bears the burden of proof. For example, the Appellate Body, in EC - Hormones, states as follows: ‘… The initial burden lies on the complaining party, which must establish a prima facie case of inconsistency with a particular provision of the SPS Agreement on the part of the defending party, or more precisely, of its SPS measure or measures complained about. When that prima facie case is made, the burden of proof moves to the defending party, which must in turn counter or refute the claimed inconsistency. This seems straightforward enough and is in conformity with our ruling in United States - Shirts and Blouses, which the Panel invokes and which embodies a rule applicable in any adversarial proceedings.’” 4
As a whole, on the one hand, as ruled by the Panel in Argentina-Ceramic Floor Tiles (DS189), “[w]e recall that the burden of proof in WTO dispute settlement proceedings rests with the party that asserts the affirmative of a particular claim or defence. It implies that the complaining party will be required to make a prima facie case of violation of the relevant provisions of the WTO Agreement, which is for the defendant…to refute. In this regard, the Appellate Body has stated that ‘... a prima facie case is one which, in the absence of effective refutation by the defending party, requires a panel, as a matter of law, to rule in favour of the complaining party presenting the prima facie case’…”; 5 on the other hand, as noted in the Panel Report on US-Copyright Act (DS160), “[t]he same rules apply where the existence of a specific fact is alleged. We note that a party who asserts a fact, whether the claimant or the respondent, is responsible for providing proof thereof. It is for the party alleging the fact to prove its existence. It is then for the other party to submit evidence to the contrary if it challenges the existence of that fact”. 6
In sum, with respect to the general rules of burden of proof in the context of violation complaints, as ruled by the Panel in Japan-Film (DS44): “[w]e note that as in all cases under the WTO/GATT dispute settlement system - and, indeed, as the Appellate Body recently stated, under most systems of jurisprudence - it is for the party asserting a fact, claim or defence to bear the burden of providing proof thereof. Once that party has put forward sufficient evidence to raise a presumption that what is claimed is true, the burden of producing evidence then shifts to the other party to rebut the presumption.…”. 7Certainly, as noted by the Appellate Body in US-Shirts and Blouses (DS33), “[i]n the context of the GATT 1994 and the WTO Agreement precisely how much and precisely what kind of evidence will be required to establish such a presumption will necessarily vary from measure to measure, provision to provision and case to case”.8
(ii) Burden of Proof in case of Invoking an Exception
As discussed above, generally, the burden of proof rests upon the party, whether complaining or defending, who asserts a fact or the affirmative of a particular claim or defence. As to be shown, this rule applies equally even in case of invoking an exception.
In this context, it is a general principle of law, well-established by panels in prior GATT/WTO practice, that the party (the defendant) which invokes an exception in order to justify its action carries the burden of proof that it has fulfilled the conditions for invoking the exception. However, in the author’s view, to understand the issue concerning burden of proof in case of invoking an exception, which is different from the relatively clear burden of establishing a prima facie case of violation on the complaining party, it’s helpful to stress some points here, among which the key point is to be cautious while determine which defence is “affirmative” and therefore burdens the defendant to provide sufficient evidence to rebut the challenged violation.
In United States-Shirts and Blouses (DS33), India argues that it was “customary GATT practice” that the party invoking a provision which had been identified as an exception must offer proof that the conditions set out in that provision were met. The Appellate Body acknowledges that several GATT 1947 and WTO panels have required such proof of a party invoking a defence, such as those found in Art. XX or Art. XI:2(c)(i), to a claim of violation of a GATT obligation, such as those found in Arts. I:1, II:1, III or XI:1. Arts. XX and XI:(2)(c)(i) are limited exceptions from obligations under certain other provisions of the GATT 1994, not positive rules establishing obligations in themselves. They are in the nature of affirmative defences. It is only reasonable that the burden of establishing such a defence, i.e. invoking an exception in the nature of affirmative defences, should rest on the party asserting it. 9
However, as ruled by the Appellate Body in EC-Hormones (DS26/DS48), “[t]he general rule in a dispute settlement proceeding requiring a complaining party to establish a prima facie case of inconsistency with a provision of …[the covered agreements] before the burden of showing consistency with that provision is taken on by the defending party, is not avoided by simply describing that same provision as an ‘exception’. In much the same way, merely characterizing a treaty provision as an ‘exception’ does not by itself justify a ‘stricter’ or ‘narrower’ interpretation of that provision than would be warranted by examination of the ordinary meaning of the actual treaty words, viewed in context and in the light of the treaty's object and purpose, or, in other words, by applying the normal rules of treaty interpretation. It is also well to remember that a prima facie case is one which, in the absence of effective refutation by the defending party, requires a panel, as a matter of law, to rule in favour of the complaining party presenting the prima facie case.” 10
In short, during the process of the establishment of a violation, it’s generally up to the complainant to provide evidence concerning inconsistency, and only in case of limited exceptions the burden of proof rests upon the defending party invoking a defence in the nature of affirmative defences, such as those found in Art. XX or Art. XI:2(c)(i) of the GATT 1994.
(iii) Special Rules Concerning Non-Violation Claims
As suggested by the corresponding provisions, the most significant difference between violation complaints under Art. XXIII:1(a) of the GATT 1994 and non-violation ones under Art. XXIII:1(b) is, while, when violation complaints are brought under Art. XXIII:1(a), the infringement of an obligation of the agreements is considered prima facie to constitute a case of nullification or impairment, from the fact of violation alone, by establishing a formal presumption, such a presumption does not exist in non-violation cases.
With the lack of such a presumption, and given the nature of the factually complex disputes and particular claims of non-violation nullification or impairment, the resolution of issues relating to the proper allocation of the burden of proof is of particular importance. In case of non-violation nullification or impairment, i.e., where the application of Art. XXIII:1(b) is concerned, Art. 26.1(a) of the DSU and panel practice in the context of the WTO Agreement and GATT jurisprudence confirm that this is an exceptional course of action for which the complaining party bears the burden of providing a detailed justification to back up its allegations.
This requirement has been recognized and applied by a number of GATT panels. For example, the panel on Uruguayan Recourse to Art. XXIII noted that in cases “where there is no infringement of GATT provisions, it would be ... incumbent on the country invoking Article XXIII to demonstrate the grounds and reasons for its invocation. Detailed submissions on the part of that contracting party on these points were therefore essential for a judgement to be made under this Article”. And the panel on US - Agricultural Waiver noted, in applying the 1979 codification of this rule: “The party bringing a complaint under [Article XXIII:1(b)] would normally be expected to explain in detail that benefits accruing to it under a tariff concession have been nullified or impaired”.
Art. 26.1(a) of the DSU codifies the prior GATT practice, which provides in relevant part: “the complaining party shall present a detailed justification in support of any complaint relating to a measure which does not conflict with the relevant covered agreement ...”.