17
More in particular, it seems to me that the “general rule of interpretation” under
Article 31 VCLT fits well with the structure and nature of a treaty like UNCLOS,
which (i) consists of 320 articles and 9 annexes, (ii) contains important conflict
clauses regulating the relationship with other international agreements, (iii) is a
framework convention that needs to be supplemented by subsequent agreements
(some of which have already been concluded and are currently in force), and (iv)
can be interpreted by taking into account “any subsequent practice in the application
of the treaty which establishes the agreement of the parties regarding its
interpretation”,
10
including the practice of the International Seabed Authority (ISA)
and other international organizations exercising competences pursuant to specific
UNCLOS provisions.
In the next sections I will examine, therefore, to what extent international tribunals called upon to rule on the interpretation of UNCLOS have expressly relied on
the interpretative principles and criteria set out in Article 31 VCLT.
2 The Relevance of Good Faith
As is well known, under the VCLT a treaty must be interpreted
11
and performed
12
in
good faith.
13
In addition to these obligations, Article 300 UNCLOS provides that
“States parties shall fulfil in good faith the obligations assumed under this
Convention”. Two observations are in order about the exact scope of this provision.
In the first place, even though Article 300 UNCLOS “contains a positive injunction
on the parties to act in good faith”,
14
international jurisprudence has emphasized
that it is not an autonomous provision, since it operates only in relation to the application or interpretation of other substantive and procedural obligations imposed by
UNCLOS. For example, ITLOS has observed that
the obligation ‘to seek to agree…’ under article 63, paragraph 1, and the obligation to cooperate under article 64, paragraph 1 of the Convention are ‘due diligence’ obligations which
clusions to Governments for comments and observations. Draft conclusion 2(1) reads: “Articles 31
and 32 of the Vienna Convention on the Law of Treaties set forth, respectively, the general rule of
interpretation and the rule on supplementary means of interpretation. These rules also apply as
customary international law” (emphasis added).
10 See Arts. 31 (3) (b) VCLT.
11 See Arts. 31 VCLT.
12 See Arts. 26 VCLT. It may be recalled that already in 1910 an arbitral tribunal established under
the Permanent Court of Arbitration (PCA) ruled that “according to the principle of international
law […] treaty obligations are to be executed in perfect good faith”, PCA, The North Atlantic
Fisheries Case (Great Britain/United States of America), Award, 7 September 1910, Reports of
International Arbitral Awards, p. 188. See also Carreau and Marrella (2018), p. 161.
13 On the principle of good faith in international law see, among many others, Kolb (2000). For a
recent discussion of good faith in treaty interpretation, and for further references, see Linderfalk
(2018).
14 O’Brien (2017), p. 1939.
The ‘General Rule of Interpretation’ in the International Jurisprudence Relating…
More in particular, it seems to me that the “general rule of interpretation” under
Article 31 VCLT fits well with the structure and nature of a treaty like UNCLOS,
which (i) consists of 320 articles and 9 annexes, (ii) contains important conflict
clauses regulating the relationship with other international agreements, (iii) is a
framework convention that needs to be supplemented by subsequent agreements
(some of which have already been concluded and are currently in force), and (iv)
can be interpreted by taking into account “any subsequent practice in the application
of the treaty which establishes the agreement of the parties regarding its
interpretation”,
10
including the practice of the International Seabed Authority (ISA)
and other international organizations exercising competences pursuant to specific
UNCLOS provisions.
In the next sections I will examine, therefore, to what extent international tribunals called upon to rule on the interpretation of UNCLOS have expressly relied on
the interpretative principles and criteria set out in Article 31 VCLT.
2 The Relevance of Good Faith
As is well known, under the VCLT a treaty must be interpreted
11
and performed
12
in
good faith.
13
In addition to these obligations, Article 300 UNCLOS provides that
“States parties shall fulfil in good faith the obligations assumed under this
Convention”. Two observations are in order about the exact scope of this provision.
In the first place, even though Article 300 UNCLOS “contains a positive injunction
on the parties to act in good faith”,
14
international jurisprudence has emphasized
that it is not an autonomous provision, since it operates only in relation to the application or interpretation of other substantive and procedural obligations imposed by
UNCLOS. For example, ITLOS has observed that
the obligation ‘to seek to agree…’ under article 63, paragraph 1, and the obligation to cooperate under article 64, paragraph 1 of the Convention are ‘due diligence’ obligations which
clusions to Governments for comments and observations. Draft conclusion 2(1) reads: “Articles 31
and 32 of the Vienna Convention on the Law of Treaties set forth, respectively, the general rule of
interpretation and the rule on supplementary means of interpretation. These rules also apply as
customary international law” (emphasis added).
10 See Arts. 31 (3) (b) VCLT.
11 See Arts. 31 VCLT.
12 See Arts. 26 VCLT. It may be recalled that already in 1910 an arbitral tribunal established under
the Permanent Court of Arbitration (PCA) ruled that “according to the principle of international
law […] treaty obligations are to be executed in perfect good faith”, PCA, The North Atlantic
Fisheries Case (Great Britain/United States of America), Award, 7 September 1910, Reports of
International Arbitral Awards, p. 188. See also Carreau and Marrella (2018), p. 161.
13 On the principle of good faith in international law see, among many others, Kolb (2000). For a
recent discussion of good faith in treaty interpretation, and for further references, see Linderfalk
(2018).
14 O’Brien (2017), p. 1939.
The ‘General Rule of Interpretation’ in the International Jurisprudence Relating…