33
5 Subsequent Agreements and Subsequent Practice
in Relation to the Interpretation of UNCLOS
Overall, it appears that international courts and tribunals lean towards a coordinated
interpretation of UNCLOS provisions and the relevant rules of international law, in
order to ensure systemic integration between the two. However, they adopt a much
more cautious position when it comes to attaching value to subsequent practice as a
means of interpretation under Article 31(3) (a) and (b) VCLT.
116
Emblematic of this is the decision in the South China Sea Arbitration, in particular the paragraphs devoted to State practice in the implementation of Article 121(3)
UNCLOS.
117
The Arbitral Tribunal found that said State practice was necessarily
irrelevant to the dispute before it. To justify this negative finding,
118
the Tribunal
referred to a number of judgments by the ICJ
119
and reports by the Appellate body
of the World Trade Organization,
120
which showed that
the threshold the Court establishes for accepting an agreement on the interpretation by the
State practice is quite high. The threshold is similarly high in the jurisprudence of the World
Trade Organization, which requires ‘a concordant, common and consistent sequence of acts
or pronouncements’ to establish a pattern implying an agreement of the parties regarding a
treaty’s interpretation.
121
The Arbitral Tribunal’s cautious attitude has much to commend it.
122
To begin
with, the Tribunal relied on the same case law as cited in the ILC’s commentaries to
the 2018 Draft Conclusions on Subsequent Agreements and Subsequent Practice in
Relation to the Interpretation of Treaties,
123
in particular to Conclusion no. 9.
124
In
this regard, it must be noted that Conclusion 9 essentially reflects the ILC’s belief
that the clarity and specificity of a specific subsequent practice is the first requirement for using that practice as a means of interpretation.
125
“In addition,” as stated
in paragraph 2 of Conclusion 9, “the weight of subsequent practice under article 31,
paragraph 3 (b) [VCLT] depends, inter alia, on whether and how it is repeated”.
116 See, Nolte (2013).
117 South China Sea Arbitration (Philippines v. China), Award, paras 552–553.
118 Ibidem, para. 553: “there is no evidence for an agreement based upon State practice on the interpretation of Article 121(3)”.
119 Ibidem, footnotes 586 and 587.
120 Ibidem, footnote 588.
121 Ibidem, para. 552.
122 Contra see Song (2018).
123 See Ascensio (2018) and Kadelbach (2018).
124 ILC, Report of the work of the seventieth session (2018), pp. 71–74.
125 See ILC, Draft conclusions on subsequent agreements and subsequent practice in relation to the
interpretation of treaties, Conclusion 9, para. 1: “The weight of a subsequent agreement or subsequent practice as a means of interpretation under article 31, paragraph 3, depends, inter alia, on its
clarity and specificity”.
The ‘General Rule of Interpretation’ in the International Jurisprudence Relating…
5 Subsequent Agreements and Subsequent Practice
in Relation to the Interpretation of UNCLOS
Overall, it appears that international courts and tribunals lean towards a coordinated
interpretation of UNCLOS provisions and the relevant rules of international law, in
order to ensure systemic integration between the two. However, they adopt a much
more cautious position when it comes to attaching value to subsequent practice as a
means of interpretation under Article 31(3) (a) and (b) VCLT.
116
Emblematic of this is the decision in the South China Sea Arbitration, in particular the paragraphs devoted to State practice in the implementation of Article 121(3)
UNCLOS.
117
The Arbitral Tribunal found that said State practice was necessarily
irrelevant to the dispute before it. To justify this negative finding,
118
the Tribunal
referred to a number of judgments by the ICJ
119
and reports by the Appellate body
of the World Trade Organization,
120
which showed that
the threshold the Court establishes for accepting an agreement on the interpretation by the
State practice is quite high. The threshold is similarly high in the jurisprudence of the World
Trade Organization, which requires ‘a concordant, common and consistent sequence of acts
or pronouncements’ to establish a pattern implying an agreement of the parties regarding a
treaty’s interpretation.
121
The Arbitral Tribunal’s cautious attitude has much to commend it.
122
To begin
with, the Tribunal relied on the same case law as cited in the ILC’s commentaries to
the 2018 Draft Conclusions on Subsequent Agreements and Subsequent Practice in
Relation to the Interpretation of Treaties,
123
in particular to Conclusion no. 9.
124
In
this regard, it must be noted that Conclusion 9 essentially reflects the ILC’s belief
that the clarity and specificity of a specific subsequent practice is the first requirement for using that practice as a means of interpretation.
125
“In addition,” as stated
in paragraph 2 of Conclusion 9, “the weight of subsequent practice under article 31,
paragraph 3 (b) [VCLT] depends, inter alia, on whether and how it is repeated”.
116 See, Nolte (2013).
117 South China Sea Arbitration (Philippines v. China), Award, paras 552–553.
118 Ibidem, para. 553: “there is no evidence for an agreement based upon State practice on the interpretation of Article 121(3)”.
119 Ibidem, footnotes 586 and 587.
120 Ibidem, footnote 588.
121 Ibidem, para. 552.
122 Contra see Song (2018).
123 See Ascensio (2018) and Kadelbach (2018).
124 ILC, Report of the work of the seventieth session (2018), pp. 71–74.
125 See ILC, Draft conclusions on subsequent agreements and subsequent practice in relation to the
interpretation of treaties, Conclusion 9, para. 1: “The weight of a subsequent agreement or subsequent practice as a means of interpretation under article 31, paragraph 3, depends, inter alia, on its
clarity and specificity”.
The ‘General Rule of Interpretation’ in the International Jurisprudence Relating…