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EXÉCUTION DES JUGEMENTS
ENFORCEMENT OF JUDGMENTS
Doc. prél. No 24
Prel. Doc. No 24
décembre/December 2003
LA RELATION ENTRE LE PROJET SUR LES JUGEMENTS ET D’AUTRES
INSTRUMENTS INTERNATIONAUX
préparé par Andrea Schulz, Premier secrétaire
* * *
THE RELATIONSHIP BETWEEN THE JUDGMENTS PROJECT AND OTHER
INTERNATIONAL INSTRUMENTS
prepared by Andrea Schulz, First Secretary
Document préliminaire No 24 de décembre 2003
à l’intention de la Commission spéciale de décembre 2003
sur la compétence, la reconnaissance et l’exécution des jugements étrangers
en matière civile et commerciale
Preliminary Document No 24 of December 2003
drawn up for the attention of the Special Commission of December 2003
on Jurisdiction, Recognition and Enforcement of Foreign Judgments
in Civil and Commercial Matters
LA RELATION ENTRE LE PROJET SUR LES JUGEMENTS ET D’AUTRES
INSTRUMENTS INTERNATIONAUX
préparé par Andrea Schulz, Premier secrétaire
* * *
THE RELATIONSHIP BETWEEN THE JUDGMENTS PROJECT AND OTHER
INTERNATIONAL INSTRUMENTS
prepared by Andrea Schulz, First Secretary
2
TABLE OF CONTENTS
I. Introduction ................................................................................................. 3
II. Default rules provided by public international law in the absence of a clause in
the treaties concerned ................................................................................... 4
A. The sources of public international law and solutions provided by them .......... 4
1. The Vienna Convention on the Law of Treaties........................................ 4
a) Default rule in Article 30 concerning the relations between States
parties to both treaties in question................................................... 4
i. Treaties “relating to the same subject matter”.............................. 6
ii. Compatibility of the earlier treaty with the later one ...................... 7
iii. Lex posterior rule as default rule for remaining cases of
incompatibility .......................................................................... 9
b) Further requirements established by Article 41 of the Vienna
Convention concerning the relations between a State party to
both, and a State party only to the earlier one of the treaties in
question........................................................................................ 9
2. International customary law ................................................................12
a) Party identity................................................................................13
b) Not all parties to the earlier treaty are parties to the later one............14
c) Conclusion ...................................................................................15
3. General principles of public international law .........................................15
B. How does European Community law fit into the rules described?...................15
III. Limits established by the Vienna Convention for the content of a disconnection
clause.........................................................................................................16
IV. Conclusion ..................................................................................................16
A. All parties to the earlier treaty are party to the later treaty ..........................17
B. Not all parties to the earlier treaty become party to the later treaty ..............17
3
I. INTRODUCTION
1. Throughout the negotiations concerning a global convention on jurisdiction,
recognition and enforcement of foreign judgments in civil and commercial matters (the
Judgments Convention), it has been stressed that a number of international instruments
dealing with some or all of these issues already exist. It is therefore of great legal and
practical importance to define the relationship of the new convention with other
instruments. However, when one turns to legal doctrine for some enlightenment on this
rather technical subject, one finds that publications dealing with it in general terms and
not referring only to one or two particular treaties and their relationship, are scarce. Ian
Sinclair, a leading commentator on the Vienna Convention on the Law of Treaties,
consequently opens his respective chapter with the words:
“A particularly obscure aspect of the law of treaties is the question of application of
successive treaties which relate to the same subject-matter.”1
2. This statement will certainly be shared by many. The purpose of this paper is
therefore to describe the rules of public international law governing the relationship
between successive treaties that overlap in whole or in part, both as to their content
and/or as to the parties to them. This will be done in general terms, sometimes using
particular treaties as examples. As the explanation of the general rules will show, this
paper cannot indicate in detail for a large number of existing instruments what their
respective relationship with a future Judgments Convention would be.2
3. It will be demonstrated that, as long as parties are still at the negotiating stage, it
is first and foremost up to treaty negotiators to resolve any possible conflict between
treaties by including an adequate compatibility rule in the conventions concerned. As the
paper will show, public international law gives them a large discretion to include rules on
the relationship between different international instruments into the latter. The paper
describes possible limits set by public international law to their discretion (infra III), as
well as the default rules provided by public international law in the absence of an explicit
rule in one or more of the instruments concerned (infra II). Although the paper will show
that it is advisable, or even necessary, to insert one or more clauses on the relationship
with other instruments into the Judgments Convention, the description of the default
rules governing such relationship in the absence of a clause is necessary because (1)
many existing instruments which could overlap with the Judgments Convention do not
contain a disconnection clause, and (2) the default rules also contain some limits to the
freedom of the parties to a later treaty with regard to the content of a disconnection
clause concerning an earlier treaty.
1
Sinclair, The Vienna Convention on the Law of Treaties, 2nd
ed. 1984, p. 93. See also Sprudzs, Status of
Multilateral Treaties – Researcher’s Mystery, Mess or Muddle? American Journal of International Law (AJIL)
1972, p. 365 et seq.
2
This is due, inter alia, to the complexity of the rules which will be identified in this paper, and in particular to
the fact that their application to the relationship between any two particular treaties in question depends to a
large extent on the identification of the (hypothetical or implicit) will of States parties. This has to be concluded
from historical materials reflecting treaty negotiations, but also from a thorough examination of State practice
under the Convention(s) in question, a task that by far exceeds the resources of the Permanent Bureau given
the large number of existing instruments which might potentially overlap with the Judgments Convention.
However, a further paper on individual instruments and their relationship with the Judgments Project may
follow as soon as the Permanent Bureau receives further replies from Member States to its request to be
informed of any specific instruments to which States are parties and which they wished to be considered in both
such a paper and in the disconnection clause.
4
II. DEFAULT RULES PROVIDED BY PUBLIC INTERNATIONAL LAW IN THE ABSENCE OF A CLAUSE
IN THE TREATIES CONCERNED
A. The sources of public international law and solutions provided by them
4. The three classical sources of public international law, as listed in Article 38 of the
Statute of the International Court of Justice, are “international conventions, whether
general or particular, establishing rules expressly recognized by the contesting States”,
“international custom, as evidence of a general practice accepted as law”, and “the
general principles of law recognized by civilized nations”. All three sources are of equal
value; there exists no hierarchy between them.3
1. The Vienna Convention on the Law of Treaties
a) Default rule in Article 30 concerning the relations between States parties
to both treaties in question
5. Even in the absence of a hierarchy, however, a Treaty on the Law of Treaties is of
course the most specific source to turn to. The Vienna Convention on the Law of Treaties
of 23 May 19694
entered into force on 27 January 1980. As of 1 December 2003, 96
States were parties to it5
.6
6. The rule on the relationship of successive treaties is contained in Article 30 of the
Vienna Convention and reads as follows:
Article 30 - Application of successive treaties relating to the same subject-
matter
1. Subject to Article 1037
of the Charter of the United Nations, the rights and
obligations of States parties to successive treaties relating to the same subjectmatter
shall be determined in accordance with the following paragraphs.
2. When a treaty specifies that it is subject to, or that it is not to be considered
as incompatible with, an earlier or later treaty, the provisions of that other treaty
prevail.
3. When all the parties to the earlier treaty are parties also to the later treaty but
the earlier treaty is not terminated or suspended in operation under article 598
, the
earlier treaty applies only to the extent that its provisions are compatible with those
of the later treaty.
4. When the parties to the later treaty do not include all the parties to the earlier
one:
3
Daillier / Pellet, Droit international public, 7e éd., 2002, p. 267 no 171.
4
U.N.T.S. vol. 1155, p. 331; AJIL (1969) p. 875 et seq.
5
The following 16 Member States of the Hague Conference are not parties to the Vienna Convention: Brazil,
France, Iceland, Ireland, Israel, Jordan, Malta, Monaco, Norway, Portugal, Romania, South Africa, Sri Lanka,
Turkey, United States of America and Venezuela.
6
On the question of whether or to what extent the Vienna Convention may be considered to codify customary
law, see infra paragraphs 38 et seq.
7
Charter of the United Nations, Article 103
In the event of a conflict between the obligations of the Members of the United Nations under the present
Charter and their obligations under any other international agreement, their obligations under the present
Charter shall prevail.
8
Vienna Convention, Article 59 – Termination or suspension of the operation of a treaty implied by
conclusion of a later treaty
1. A treaty shall be considered as terminated if all the parties to it conclude a later treaty relating to the
same subject-matter and:
(a) it appears from the later treaty or is otherwise established that the parties intended that the matter
should be governed by that treaty; or
(b) the provisions of the later treaty are so far incompatible with those of the earlier one that the two
treaties are not capable of being applied at the same time.
2. The earlier treaty shall be considered as only suspended in operation if it appears from the later treaty or
is otherwise established that such was the intention of the parties.
5
(a) as between States parties to both treaties the same rule applies as in
paragraph 3;
(b) as between a State party to both treaties and a State party to only one of
the treaties, the treaty to which both States are parties governs their mutual
rights and obligations.
5. Paragraph 4 is without prejudice to article 419
, or to any question of the
termination or suspension of the operation of a treaty under article 6010
or to any
question of responsibility which may arise for a State from the conclusion or
application of a treaty the provisions of which are incompatible with its obligations
towards another State under another treaty.
7. The following paragraphs will first examine which one of several successive treaties
will have to be applied under Article 30 of the Vienna Convention, if and as far as the
parties are identical and none of the treaties in question contains explicit rules on the
relationship with other instruments. The words “if and as far as the parties are identical”
refers to Article 30(3) and (4)(a). In other words, it will be discussed which treaty
prevails in the mutual relationship between States parties to all treaties in question in
cases where either (1) all States parties to an earlier treaty are also parties to the more
recent treaty, or (2) only some States parties to the earlier treaty are parties to the later
treaty. If the rules described below lead to the result that a particular treaty “prevails”,
this means that a judge in a State party to both conflicting treaties in question would
have to apply the prevailing one in the mutual relationship with the other State
concerned which is equally party to both treaties.11
As the discussion below will
9
Vienna Convention, Article 41 – Agreements to modify multilateral treaties between certain of the
parties only
1. Two or more of the parties to a multilateral treaty may conclude an agreement to modify the treaty as
between themselves alone if:
(a) the possibility of such a modification is provided for by the treaty; or
(b) the modification in question is not prohibited by the treaty and:
(i) does not affect the enjoyment by the other parties of their rights under the treaty or the
performance of their obligations;
(ii) does not relate to a provision, derogation from which is incompatible with the effective
execution of the object and purpose of the treaty as a whole.
2. Unless in a case falling under paragraph 1(a) the treaty otherwise provides, the parties in question
shall notify the other parties of their intention to conclude the agreement and of the modification to the
treaty for which it provides.
10
Vienna Convention, Article 60 – Termination or suspension of the operation of a treaty as a
consequence of its breach
1. A material breach of a bilateral treaty by one of the parties entitles the other to invoke the breach as a
ground for terminating the treaty or suspending its operation in whole or in part.
2. A material breach of a multilateral treaty by one of the parties entitles:
(a) the other parties by unanimous agreement to suspend the operation of the treaty in whole or in
part or to terminate it either:
(i) in the relations between themselves and the defaulting State, or
(ii) as between all the parties;
(b) a party specially affected by he breach to invoke it as a ground for suspending the operation of
the treaty in whole or in part in the relations between itself and the defaulting State;
(c) any party other than the defaulting State to invoke the breach as a ground for suspending the
operation of the treaty in whole or in part with respect to itself if the treaty is of such a character
that a material breach of its provisions by one party radically changes the position of every party
with respect to the further performance of its obligations under the treaty.
3. A material breach of a treaty, for the purposes of this article, consists in:
(a) a repudiation of the treaty not sanctioned by the present Convention; or
(b) the violation of a provision essential to the accomplishment of the object or purpose of the treaty.
4 The foregoing paragraphs are without prejudice to any provision in the treaty applicable in the event of
a breach.
5. Paragraphs 1 to 3 do not apply to provisions relating to the protection of the human person contained
in treaties of a humanitarian character, in particular to provisions prohibiting any form of reprisals against
persons protected by such treaties.
11
See infra note 35 and the adjoining text for a discussion of when a case is limited to the mutual relationship
of two States parties to both agreements, and when it would affect the rights of other States parties only to the
earlier treaty.
Whether this infringes upon the rights of other States who are only party to one but not to the other
treaty is a question of State responsibility incurred by concluding two conflicting treaties, but it does not have
any impact, under the Vienna Convention, on the fact that the (conflicting) obligations of the two treaties are
both validly binding upon the State concerned. This issue will be dealt with separately, infra, under b).
6
show, in the absence of a clause the prevailing treaty would normally be the more
specific one, no matter whether it is earlier or later than the more general treaty (see
infra i). If none of the instruments concerned is more specific than the other, the more
recent treaty will prevail in case of incompatibility of individual provisions (see infra ii).
i. Treaties “relating to the same subject matter”
8. Article 30(2)-(5) apply where successive treaties relate “to the same subjectmatter”
(Article 30(1)). This expression has to be construed narrowly,12
meaning “the
same degree of generality”.13
In deciding this, one has to consider the treaty as a whole
and not any individual provision.
9. An example of treaties relating to the same subject matter is provided by the
Conventions of Brussels14
(1968) and Lugano (1988) on Jurisdiction and the Enforcement
of Judgments in Civil and Commercial Matters, on the one hand, and the Preliminary
Draft Hague Convention on Jurisdiction and Foreign Judgments in Civil and Commercial
Matters (1999), all three of them possessing the same level of generality.
10. According to the prevailing opinion, we are on the other hand not faced with two
treaties that “relate to the same subject-matter” where a general treaty impinges
indirectly on the content of a particular provision of an earlier, more specific treaty.
Accordingly, a general treaty on the reciprocal enforcement of judgments does not affect
the continued applicability of particular provisions concerning the enforcement of
judgments contained in an earlier treaty dealing with third party liability in the field of
nuclear energy.15
This narrow interpretation of the words “relating to the same subject
matter” is used because, although the rule lex specialis derogat legi generali is commonly
recognised in public international law, it was not incorporated into the Vienna Convention
explicitly as a counter-balance to the rule lex posterior derogat legi priori. Hence, by
giving the words “relating to the same subject-matter” the narrow meaning described
earlier, it is possible at the interpretation stage, and without having recourse to the rule
giving precedence to the more recent treaty, to apply the unwritten rule of precedence of
the more specific treaty.16
Accordingly, the partial overlap described in this example
would not be sufficient for the application of Article 3017
but interpretation would lead to
the conclusion that parties would want the more specific treaty to prevail in their mutual
relations, although it is older.
11. Things become more difficult, however, when it comes to defining “generality” and
“specificity” in cases where two specific treaties overlap in part. What, if one of the
12
Sinclair (supra note 1), p. 98.
13
Daillier / Pellet (supra note 3), p. 271 no 173.
14
Although the Brussels Convention is only open to Member States of the European Union (EU) (and at the
same time part of the Acquis communautaire, adherence to which is compulsory for these States), it is still a
treaty under public international law and not European Community law proper. While the Brussels Convention
still exists and applies between Denmark, on the one hand, and all the other EU Member States, it has been
replaced by the largely identical Regulation (EC) No 44/2001, OJ EC No L 12 of 16 January 2001, p. 1, in the
relationship between all fifteen EU Member States with the exception of Denmark. This Regulation will be dealt
with under B., where the position of secondary European Community law is being discussed. Like the Brussels
Convention, the largely identical Lugano Convention is also a treaty under public international law.
15
Sinclair (supra note 1), p. 98; see also Daillier / Pellet (supra note 3), p. 272 no 173 (2. a), who equally
stress that the Vienna Convention does not contain any rule for this situation.
16
Zuleeg, Vertragskonkurrenz im Völkerrecht, Teil I: Verträge zwischen souveränen Staaten, German Yearbook
of International Law (GYIL) 20 (1977) p. 246 (257). See also infra paragraph 13.
17
Others have a wider understanding of the notion “relating to the same subject matter”, considering also, e.g.,
a general treaty on recognition and enforcement in civil and commercial matters, and a treaty on the
recognition and enforcement of maintenance decisions as treaties “relating to the same subject-matter”, thus
making their relationship a case where Article 30(3) would be applicable. Those who defend this position
consider a partial overlap of two instruments to be sufficient for the application of Article 30. See, in particular,
Volken, Konventionskonflikte im internationalen Privatrecht, 1977, p. 296-299. But see also infra note 18.
7
treaties in question is more specific in that it relies on a procedural element as the only
criterion for jurisdiction (e.g. a choice of court clause) but covers a wide range of subject
matters, while the other treaty relies on subject matter as the decisive element, e.g. a
treaty regulating some intellectual property rights (containing substantive rules as well as
rules on jurisdiction, with or without mentioning choice of court clauses)?
12. On the one hand, one could argue that the instrument focussing on jurisdiction
based on choice of court clauses, and the recognition and enforcement of the resulting
judgments, only, is more specific than a treaty dealing with substantive aspects as well
as with a wider range of jurisdictional bases. But on the other hand, one could also look
at the scope ratione materiae and argue that the latter is more narrowly defined in the
instrument on intellectual property, thus making the latter the more specific one.
13. If one considers one of the instruments to be more specific, Article 30 of the Vienna
Convention would not be applicable. As in the example given above, treaty interpretation
would lead to the conclusion that the more specific instrument prevails, no matter
whether it is earlier or later in time. If, however, one concludes that the two treaties are
of the same level of generality, the further conditions for the application of Article 30 as
described below will have to be examined.
14. To give another example: Would a treaty governing jurisdiction based on choice of
court clauses for a wide range of subject matters be considered as relating “to the same
subject-matter” as a treaty governing jurisdiction based on a general defendant’s forum,
submission, counter-claims, joinder (multiple defendants) for the same class of subjectmatters?
While as to the substantive law issue dealt with, both treaties do indeed
possess the same level of generality, one is more specific when it comes to the range of
jurisdictional bases, focussing only on choice of court agreements. If one focuses on this
latter specificity, in their respective relationship, treaty interpretation would lead to the
conclusion that the more specific instrument prevails.18
If one focuses on the same level
of generality as to subject-matters covered, this would be a case for Article 30 of the
Vienna Convention, ultimately leading to the question whether there is compatibility
between the two. Discussion of the latter (see infra under ii) will show that in case of
incompatibility, normally the more recent treaty prevails.
15. To sum up, all examples given only demonstrate how urgent it is to actually include
disconnection clauses into the treaties concerned, because treaty interpretation, already
when it comes to deciding whether two treaties relate to the same subject matter and /
or which one may be more specific, can lead to rather unpredictable results.
ii. Compatibility of the earlier treaty with the later one
16. Where the two treaties in question do relate to the same subject matter, and the
issue of the relationship between them thus remains within the scope of Article 30 of the
Vienna Convention, the next question to be answered is whether their provisions are
“compatible” within the meaning of Article 30(2) and (3). At this level, the question has
to be answered by looking at the individual provisions in the two treaties in question and
the results that their application would produce in a particular case. Hence, this is no
longer a matter of comparing the two treaties as a whole in abstract terms, as it was
when identifying their respective subject-matter.
18
See Sinclair (supra note 1), p. 93, 98 on the rule generalia specialibus non derogant. Volken,
Konventionskonflikte (supra note 17), p. 297-299, who favours the application of Article 30 of the Vienna
Convention also in cases of partial overlap between two instruments, comes to the same result by stating that
the typical conflict between legislative private international law treaties is not fully and appropriately dealt with
by Article 30(2) of the Vienna Convention. In his example cited supra note 17, he therefore assumes that the
will of the parties and the general principle of lex specialis derogat legi generali will let the special instrument
on maintenance prevail.
8
17. The basic rule for successive treaties, to which Article 30(3) refers, is contained in
Article 5919
of the Vienna Convention. It states that normally, where the parties to a
treaty conclude a later treaty relating to the same subject matter, in case of
incompatibility the earlier treaty shall be considered as terminated. Only where the will of
the parties leads us to assume that they wanted both treaties to coexist, Article 30(3)
comes into play.20
18. Consequently, the point of reference is the later treaty: if it may be assumed that
parties wanted both treaties to continue to apply, provisions of the earlier treaty only do
so to the extent that they21
are compatible with the provisions of the later treaty. In case
of incompatibility, the lex posterior prevails (see infra under iii).
19. No incompatibility exists where the two or more instruments applicable to a certain
factual situation would lead to the same result.22
The Vienna Convention does not decide
the rather academic question which of the instruments prevails in such a case. But not
even the mere difference of results would necessarily mean that there is
incompatibility:23
only where (1) two or more conventions apply to the same factual
situation24
and (2) the pertinent legal rules in such conventions provide for
contradictory results,25
there is incompatibility calling for the application of Article 30(3)
of the Vienna Convention and the precedence of lex posterior.
20. An example given on various occasions is the coexistence of an earlier regional
instrument, negotiated among States between whom there is a high degree of mutual
confidence, and another negotiated within the framework of a universal organisation.
Where the parties to the earlier, regional treaty have granted each other wide rights
based on mutual trust or even some approximation or integration of their legal systems,
the circumstances or the intention of the parties might lead to the conclusion that in their
mutual relations, this earlier, more generous treaty shall continue to apply between
them, even if the same parties, together with others, have later agreed on a treaty on
the same subject matter at a global level but providing for a more restricted regime.26
Thus, although the results may be different when applying one or the other treaty, the
wider rights granted by the earlier treaty are not incompatible27
with the more restrictive
regime adopted by the more recent global instrument. In this case, treaty interpretation
would resolve the question of the relationship between the two instruments.
21. Another example along the same lines: Assuming that all States parties to the
Conventions of Brussels and Lugano would become parties to a Judgments Convention in
the form of the 1999 Draft relating to the same subject-matter28
and in the absence of a
19
Supra note 8.
20
Volken, Konventionskonflikte (supra note 17), p. 297 et seq.
21
This decision may be taken separately for individual provisions within the treaties in question (Zuleeg (supra
note 16), GYIL 20 (1977) p. 246 (273)).
22
Volken, Conflicts between Private International Law Treaties, in: Heere (ed.), International Law and The
Hague’s 750th
Anniversary, 1999, p. 149 (152, 155).
23
Sinclair (supra note 1), p. 97 with further references from the negotiating history of the Vienna Convention.
24
In order to determine this, one has to examine (1) the scope ratione materiae, (2) the scope ratione
personae, (3) the scope ratione loci and (4) the scope ratione temporis (Volken, supra note 22, (155)). Only
where all four elements are fulfilled for each of the treaties in question, there can be a conflict of conventions
that needs to be resolved by public international law.
25
Volken (supra note 22), p. 155.
26
Sinclair (supra note 1), p. 97, 98, who gives the example of a consular treaty. In our opinion this would be all
the more true where the regional agreement is a closed one, open only to a certain group of States parties, like
the Brussels Convention of 1968, because States parties to it, if they wanted to have an – even identical –
agreement on the same subject-matter with third States, could not simply invite the latter to join the existing
treaty but needed to conclude a new one. While Daillier / Pellet (supra note 3), p. 272, no 173, 2. a), state that
in a case as described by Sinclair, where the regional treaty is the earlier one, and in the case of silence of the
subsequent global treaty, the lex posterior would prevail, they add that this would be “in conformity with the
implicit will of the parties”. Hence, everything depends on interpreting the treaties in question in order to
identify that will.
27
This is often difficult to decide and has to be determined by treaty interpretation (Zuleeg (supra note 16),
GYIL 20 (1977) p. 246 (256)).
28
See supra paragraph 9.
9
disconnection clause in the latter, application of the compatibility rule of the Vienna
Convention would produce the following results:
22. The three texts are identical to a large extent, but where they are not, results may
be slightly different (see, e.g., minor differences such as domicile v. habitual residence as
a general defendant’s forum; differences in the jurisdiction rules on contracts and torts).
23. Concerning their compatibility, it has to be borne in mind that one of the most
important features of the Conventions of Brussels and Lugano is that judgments from
another Contracting State shall be recognised by operation of law and declared
enforceable without any further examination in all other Contracting States of whether
the court of origin had jurisdiction under the Convention. Therefore, it can be
argued that by including a rule in the Judgments Convention (1999) obliging the judge in
the requested State to examine jurisdiction of the court of origin (which is due to the
concept of a mixed as opposed to a double convention), the States parties to the
Conventions of Brussels and Lugano had not intended to terminate the more advanced
system in place between them, which was based on further integration, harmonisation
and confidence. Therefore, treaty interpretation would lead to the result, like in the
example given supra in paragraph 20 , that results were different but not incompatible.
The States parties to the earlier instrument would wish to continue to apply it to the
recognition and enforcement of judgments from other States parties. Although this leads
to precedence of the earlier treaty instead of the precedence of lex posterior as
established by the Vienna Convention, the result can also be sustained under
Article 30(3) because the wider-reaching provisions of the earlier treaty are not
“incompatible” with the narrower regime covering a larger number of parties which is set
up by the later treaty.
iii. Lex posterior rule as default rule for remaining cases of incompatibility
24. For the remaining cases where (1) the successive treaties relate to the same
subject matter, i.e. are of the same degree of generality or specificity, (2) treaty
interpretation leads to the conclusion that the earlier treaty was not intended to be
terminated, and (3) treaty interpretation does not, as in the example just given, lead to
the conclusion that the parties wanted the earlier treaty to prevail,29
Article 30(3) and (4)
establish the priority of the lex posterior as a default rule to the extent that the parties to
both instruments are identical:
25. Paragraph 3 deals with full party identity (i.e. all parties to the earlier treaty are
also party to the later treaty). Where treaty interpretation does not lead to any different
conclusion,30
the earlier treaty only applies to the extent that its provisions are
compatible with those of the later treaty. In other words, in case of a conflict, the more
recent treaty prevails.
26. As far as the mutual relations between States parties to both conventions are
concerned, the same rule applies even in cases where not all parties to the earlier treaty
are also parties to the later one (Article 30(4)(a)).
b) Further requirements established by Article 4131
of the Vienna Convention
concerning the relations between a State party to both, and a State party
only to the earlier one of the treaties in question
27. Article 30(4)(b) clarifies the obvious, namely that States that are not party to all of
the treaties in question remain unaffected by a treaty to which they are not a party. E.g.
29
Volken, Konventionskonflikte (supra note 17), p. 297 et seq., reduces Article 30(3) to cases where both
treaties only partially overlap (which is admittedly a typical case where the will of the parties would plead for
continuing applicability of successive treaties). However, one may have doubts as to whether these cases are
covered by Article 30 at all, given the prevailing narrow interpretation of the expression that the two treaties
must relate to the same subject-matter (see supra paragraphs 10 et seq.).
30
See previous paragraph.
31
Supra note 9.
10
where out of 30 States parties to an earlier treaty, 20 enter into a new one, the old
treaty still governs the relations among the 10 States not party to the new treaty, as well
as between each of them and each of the 20 States parties to both treaties, respectively.
28. Article 30(5) states that paragraph 4 applies “without prejudice to Article 41”, a
provision which protects the interests of States parties only to the earlier treaty by
establishing some conditions for the lawfulness of a modification of such treaty between
some of the States parties only.32
While an “amendment” is a formal change to a treaty
intended to alter its provisions with respect to all the parties, a “modification” is an inter
se agreement concluded between certain of the parties to a treaty only, and intended to
vary provisions of that treaty between themselves alone. The modification of an existing
treaty can therefore be similar to, if not identical with, the situation just described when
discussing Article 30(4)(a). The application of an existing treaty can be changed by
concluding an explicit agreement aimed at modifying this particular treaty, but the same
effect can be created by just adding a subsequent treaty between (some of) the same
parties, which would have an impact on the application of the earlier treaty between
them. For this reason, if not all the parties to the earlier treaty are also parties to the
later one,33
any subsequent treaty having a direct impact on the inter se application of
the earlier treaty between parties to both treaties has to comply with the conditions set
out in Article 41 for the modification of a treaty in order to be lawful in relation to the
other parties to the earlier treaty.34
29. These conditions are the following:
?? Where the earlier treaty explicitly provides for the possibility of inter se
modification between two or more States parties, this may be done
(Article 41(1)(a));
?? Where the earlier treaty does not explicitly provide for the possibility of inter se
modification, but does not prohibit the modification in question, either
(Article 41(1)(b)), and
- the modification in question does not affect the enjoyment by other States
parties of their rights under the treaty or the performance of their
obligations (Article 41(1)(b)(i)), and
32
See Sinclair (supra note 1), p. 106-107, and Articles 40, 41 of the Vienna Convention.
33
Shortly after the adoption of the Vienna Convention, the succession of (different) treaties on the one hand
(Article 30 of the Vienna Convention), and the amendment or modification of a particular treaty, on the other
hand (Articles 39-41 of the Vienna Convention), were looked at as two separate issues. Zuleeg (supra note 16),
GYIL 20 (1977) p. 246 (261), reduces Article 41 to cases where a sub-group of States parties to an earlier
treaty concludes a modifying treaty. As soon as a State who is not party to the earlier treaty joins the later one,
this is, according to Zuleeg, no longer a case for Article 41, even as far as the sub-group that was also party to
the earlier treaty is concerned. This rather formalistic approach has nowadays been replaced by an approach
looking at the content of the successive agreements rather than at the number of parties alone. A new standalone
treaty can have the effect of amending the provisions of an earlier treaty between those States parties to
both treaties even if there are additional States parties only to the more recent instrument.
Because Article 41 subjects the modification of an existing treaty in the inter se relations between some of the
parties to some conditions while the freedom to conclude new treaties, backed up by the default rule giving
precedence to the lex posterior in case of incompatibility in Article 30(3) and (4), seems almost unlimited,
Sinclair (supra note 1), p. 109, stated: “In practice, it may be that would-be ‘modifying’ States will seek to
overcome this difficulty by the simple device of concluding a completely new Convention”. Volken,
Konventionskonflikte (supra note 17), p. 300, therefore correctly states that the lines between treaty revision,
inter se modifications and successive (separate) treaties are difficult to draw. Hence, the more recent
interpretation, which therefore requires Article 41 to be applied in addition to Article 30, thereby preventing
such circumvention, appears convincing.
34
See, e.g., Daillier / Pellet (supra note 3), p. 273 no 173. This opinion seems to prevail today, and is
supported by the reference to Article 41 in Article 30(5). As will be demonstrated, however, in order to make
the new treaty (i.e. the modification) unlawful and thus create some State liability of a State party to both
treaties towards States parties to the earlier treaty only, the impact of the new treaty on relations between a
State party to both, and a State party to the earlier treaty only must reach a certain level. A mere “affection” of
the State party to the earlier treaty without touching upon its rights or obligations is not enough (Sinclair
(supra note 1), p. 99).
11
- does not relate to a provision, derogation from which is incompatible with
the effective execution of the object and purpose of the treaty as a whole
(Article 41(1)(b)(ii)),
inter se modification is equally permitted.
30. In other words, any modification of an existing treaty may only have relevant legal
effect inter se, i.e. in the mutual relationship between States parties to both the original
treaty and the modification in order to be lawful. As soon as the modification impinges on
the rights of States parties to the original (or earlier, in the terms of Article 30) treaty
but not to the modification (or to the later treaty, in terms of Article 30), or derogates
from a core provision, derogation from which is incompatible with the effective execution
of the object and purpose of the earlier treaty as a whole, this is contrary to
Article 41(1)(b)(i) and a breach of the earlier obligation.
31. Whether the modification does indeed affect rights of States that are parties to the
earlier treaty only, is – just like the question of (in)compatibility of successive treaties
between the same parties - not easy to determine. It is a question of interpretation and
depends very much on the nature and purpose of the (earlier) treaty in question, and on
the context in which is to be seen.35
One would have to clearly identify the “rights”
granted or protected by the earlier treaty before being able to assess whether a
particular modification affects their enjoyment.
32. But even where the modification (or the later treaty) does not affect the “enjoyment
of a right” of a State party to the earlier treaty only, it can still be in breach of that treaty
under Article 41(1)(b)(ii) of the Vienna Convention because it relates to a provision,
derogation from which is incompatible with the effective execution of the object and
purpose of the treaty as a whole.
33. If the example described in footnote 35 does not fall into the first category of
violating a right, it will at least fall into the second category of hampering the effective
execution of the object and purpose of the earlier treaty as a whole by replacing one
exclusive jurisdiction by a different one, where this interferes with an exclusive basis of
jurisdiction legitimately claimed by a State party only to the earlier agreement.
34. It is important to note, though, that in light of what was said under Article 3036
, the
modification would not be invalid, even if it was in violation of the conditions set out in
Article 41. Where there is an incompatibility of the two successive agreements and the
conclusion of the modifying agreement represents a breach of Article 41 towards third
States party to the earlier instrument only because it necessarily affects their rights (e.g.
35
Zuleeg (supra note 16), GYIL 20 (1977) p. 246 (257). One could take the example of a number of States
which have concluded a treaty on jurisdiction, recognition and enforcement, and the only basis of (exclusive)
jurisdiction is the nationality of a particular person (e.g. of the child in cases of child protection measures). Let
us assume that later, some of the States parties enter into a new agreement doing away with nationality and
focusing on the habitual residence instead, and in addition accept to recognise and enforce decisions from other
States parties to this more recent agreement without examining whether the State rendering the decision had
jurisdiction under the instrument. If States A, B and C are parties to the earlier treaty, and only States A and B
are parties to the later one, could State C claim a violation of its rights where the courts of State A take a child
protection measure concerning a national of State C, basing their jurisdiction on the habitual residence of the
child, and then State B recognises this decision under the later treaty? Both treaties relate to the same subject
matter, and assuming that they both provide for exclusive jurisdiction, albeit on a different basis, it may be
assumed that they are incompatible, and therefore the more recent treaty would prevail in the relations
between A and B. But is the case given as an example really a case only between A and B, where the child
has the nationality of State C, and C has a treaty with A and B under which it can claim exclusive jurisdiction
over that same child which is its national? C is not a party to the new treaty, so between A and C, and B and C,
the old treaty would continue to apply. Does it give C a right to have its jurisdiction based on nationality
respected by the other parties? One could well be of this opinion. Or would A and B assume that a judgment
rendered in State A on the basis of the habitual residence of the child (regardless of him or her being a national
of State C) and enforced in State B (because it originated in State A) did only concern the mutual relationship
of A and B?
36
See also Article 61(2) of the Vienna Convention.
12
where it is practically impossible for the State that concluded the conflicting treaties to
comply with two opposing duties), the Vienna Convention rule still gives precedence to
the (albeit illicit) lex posterior while holding the State concerned liable for the breach.37
35. No existing treaty which overlaps with the Judgments Convention and explicitly
permits inter se modification would strike one’s eye.38
In fact, Conventions often39
tend
to be silent on this. So the decisive questions to be answered on a case-by-case basis
(i.e. for each Convention and its relation to the Judgments Convention individually) would
be whether the envisaged modification would affect the enjoyment by other States
Parties of their rights under the treaty, or the performance of their obligations; or
whether it relates to a provision, derogation from which would be incompatible with the
effective execution of the object and purpose of the treaty as a whole.
2. International customary law
36. There are several reasons why, despite the existence of the Vienna Convention on
the Law of Treaties, it is worthwhile to equally examine the respective rules contained in
international customary law: (1) Not even all Member States of the Hague Conference
are parties to the Vienna Convention, let alone all States of the world. The Judgments
Convention, however, would probably be open to any State, including non-Member
States of the Hague Conference. It is therefore likely that States who are not parties to
the Vienna Convention may become parties to the Judgments Convention. (2) As has
been shown, even in relations between States parties to the Vienna Convention the
narrow interpretation given to the requirement that the successive treaties must relate to
“the same subject matter” very quickly leads us outside of the scope of Article 30 of the
Vienna Convention, and into other sources of public international law. (3) Since Private
International Law (PIL) treaties were not explicitly covered by the preparatory work
preceding the elaboration of the Vienna Convention, some of its provisions may seem to
37
This rule, however, has been largely – and, since Article 41 only has a residuary character, also legitimately obviated
by State practice. In fact, States concluding a modifying agreement – or a separate later treaty –
which may be contrary to an earlier treaty obligation, often include a clause into the new instrument to the
effect that the rights of third States parties to the earlier treaty are not affected (which can mean a suspension
of some of the effects of the new instrument), and a clause obliging States party to the more recent agreement
to take the necessary steps to bring their conflicting obligations in line. As long as this has not been done, the
earlier instrument then remains unaffected by the new one. See the examples given by Daillier / Pellet (supra
note 3), p. 274 no 173, in particular the example of Article 307 of the EC Treaty. Although the authors plead for
the “affirmation” of the precedence of the earlier treaty if the later one is in breach of it, it seems, that this plea
is aimed at affirmation by the parties concerned, by way of including the said clauses into the second treaty,
and not at automatic invalidity of the later treaty by operation of law.
Since this paper is intended to inform treaty negotiators of their possibilities, it is for them to ensure that they
include an appropriate compatibility clause. If they fail to do so, a practitioner having to decide which of the
conflicting treaties to apply would have to observe the rules set out in Article 30, regardless of whether the
second treaty might constitute a breach of Article 41.
38
The 1971 Hague Convention on the Recognition and Enforcement of Foreign Judgments in Civil and
Commercial Matters, e.g., is rather restrictive. In order to become operative in the bilateral relations between
two States parties, it requires the conclusion of a bilateral Supplementary Protocol, and the issues that may be
addressed in such Agreement are listed exhaustively in the Convention itself (see Articles 21 and 23). But even
in the absence of a Supplementary Agreement, Article 25 of the Convention limits the freedom of the
Contracting Parties to conclude between themselves other Conventions relating to the recognition and
enforcement of Judgments within the scope of the 1971 Convention “unless they consider it necessary, in
particular, because of economic ties or of particular aspects of their legal systems”. It seems, however, that this
restriction can be overcome (1) because of the limited number of States parties to the 1971 Convention and (2)
the opening clause contained in Article 25, allowing States parties to conclude other agreements if “they
consider it necessary”.
The 1965 Hague Convention on the Choice of Court does not contain any similar limitation.
39
Examples of provisions allowing for bilateral or multilateral agreements among some Contracting States
which would modify the original treaty are provided outside the area concerning the Judgments Project by
Article 6 of the 1954 Hague Convention relating to Civil Procedure, Articles 3(2) and 8 of the 1961 Hague
Convention Abolishing the Requirement of Legalisation for Foreign Public Documents, Articles 11, 20 and 25 of
the 1965 Hague Convention on the Service Abroad of Judicial and Extrajudicial Documents in Civil or Commercial
Matters , Article 36 of the 1980 Hague Convention on the Civil Aspects of International Child Abduction, and
Article 39(2) of the 1993 Hague Convention on Protection of Children and Co-operation in Respect of
Intercountry Adoption.
13
take very little account of PIL treaty specificities. The PIL treaties are legislative treaties,
not treaties dealing with direct transactions between States. Hence, some doubt that PIL
treaties as such are covered by the Vienna Convention. (4) The Brussels Convention of
1968, which is an important instrument to be disconnected from the Judgments Project –
and there are others – predates the Vienna Convention which, according to its Article 4,
only applies to treaties concluded after its entry into force (January 1980).
37. International customary law is created by a constant and uniform usage practiced
by the States in question, combined with their opinio juris.40
38. At the time the Vienna Convention on the Law of Treaties was being negotiated, no
general common State practice on the thorny issue of “conflicts of conventions” could be
identified.41
Therefore, although the Vienna Convention is considered to be largely a
codification of customary public international law, so that many rules contained in the
Convention also apply to States which are not parties to it, this is only partly42
the case
in the area of conflicts between conventions.
39. Some principles embodied in Article 30 of the Vienna Convention, however, may be
regarded as principles of international customary law:
40. At the time of negotiation of the Vienna Convention, reference was made to the
case-law of the International Court of Justice (ICJ) and its predecessor, the Permanent
Court of International Justice (PCIJ), in particular in order to resolve the dispute de lege
ferenda as to whether the conclusion of a more recent treaty which violated obligations
that a State party to it had undertaken towards another State in an earlier treaty, should
lead to the invalidity of the new treaty, or just create some liability of the infringing
State.43
The decisions mentioned plead in favour of validity, thus following the same lines
as the rules adopted in the Vienna Convention.44
Therefore, the fact that a more recent
treaty is in breach of an earlier one does not make the more recent treaty invalid. This
means, consequently, that it has to be decided which one to apply in the individual case.
a) Party identity
41. As to the question which of two successive treaties would prevail in case of a
conflict and in the absence of clauses dealing with this question in the treaties concerned,
treaty interpretation is the first step when trying to resolve the question. A customary
interpretative principle – which even has to be applied within the scope of the Vienna
Convention because the latter does not contain any rule on this45
- is the principle lex
specialis derogat legi generali. As far as all parties to successive treaties are
identical, it may be assumed that it reflects their will to give precedence to the more
specific instrument.46
40
Asylum Case (Colombia v. Peru), Judgment, 20 November 1950, I.C.J. Reports (1950), p. 266 (276 et seq.);
Brownlie, Principles of Public International Law, 6th
ed. 2003, p. 6 et seq.
41
See, e.g., the description of varying State practice within different international organisations by Sinclair
(supra note 1), p. 94-95. This existing variety led to the inclusion of the last part of Article 5 of the Vienna
Convention, preserving practices within any such international organisation.
42
See Zuleeg (supra note 16), GYIL 20 (1977) p. 246 (247, footnote 4) on the opposed views even within the
International Law Commission during the elaboration of the Vienna Convention as to whether the latter only
codified existing customary law in this area, or whether it established new rules.
43
See in this respect, e.g., Permanent Court of International Justice, Opinion 8 December 1927 No 14 –
European Commission of the Danube, P.C.I.J. Series B (1927), p. 22 (23); Judgment 12 December 1934 No 63
- Oscar Chinn, P.C.I.J. Series A/B (1934), p. 66 (80). The dissenting Judges van Eysinga (p. 135) and
Schücking (p. 149) had claimed nullity of the later treaty because of its conflict with the earlier one but the
Court did not follow this approach.
44
Zuleeg (supra note 16), GYIL 20 (1977) p. 246 (249 et seqq.). Although the decisions emanating from these
two courts are only binding on the States parties to the proceedings, it is recognised that the decisions can
contribute to the emergence of new State practice and, consequently, new customary international law.
45
Zuleeg (supra note 16), GYIL 20 (1977) p. 246 (256 et seq.).
46
See, e.g., Zuleeg (supra note 16), GYIL 20 (1977) p. 246 (256 with further references to the case-law of the
P.C.I.J. in footnote 44).
14
42. In the same situation of full party identity, where none of the instruments is more
specific, but they do relate to the same subject-matter and possess the same level of
generality, the rule lex posterior derogat legi priori is to be applied in case of
incompatibility.47
b) Not all parties to the earlier treaty are parties to the later one
43. Concerning the amendment or modification of a treaty, it was noted already when
the Vienna Convention was negotiated that State practice diverged to some extent from
what was often asserted to be the rule of customary international law, namely, that a
treaty may not be revised without the consent of all the parties.48
Hence, also in cases
where there is no identity of all the parties to both treaties, as far as there is party
identity and the mutual relations of these States are concerned, the same rules as above
may be applicable at least to some extent, depending, however, very much on the
interpretation of the treaties in question. This seems to be true for the lex specialis rule.
44. However, where none of the treaties in question is more specific, at an abstract and
general level, neither precedence of the lex prior nor of the lex posterior have been
generally accepted as default rules of unwritten public international law. The same is true
for a number of further approaches.49
45. Although a treaty like the Vienna Convention, even where it does not reflect
existing customary law at the time of its adoption, can lead to a change of practice and,
as a consequence, to the generation of new international customary law,50
this has not
happened in the area discussed here either - inter alia because the Vienna Convention
only contains default rules which apply unless provided otherwise by the parties,51
thus
leaving the issues largely to party autonomy of the Contracting States which has allowed
a wide variety of State practice to continue to flourish.52
Although there are doubts
whether the rule already amounts to customary law, one of the few things which seem to
be established in State practice by now, as mentioned above, is the fact that a
multilateral treaty may in practice be amended by another multilateral treaty which
comes into force only for those States which become bound by it, thus not requiring
agreement among all the parties to the earlier treaty.53
The rule of pacta sunt servanda,
as well as the so-called relativity of treaty relationships, would moreover lead to the
application of the treaty to which both States are party in their mutual relationship, no
matter whether one of them has engaged in – possibly incompatible – obligations with (a
group of) other States.
46. Where practical compliance with both treaties is factually impossible in case of a
conflict between different treaties involving not fully identical parties, in the absence of
explicit clauses it is left to the State bound by the two conflicting treaties vis-à-vis
different partners to make a policy choice which duty to comply with. Public
international law does not give any guidance as to which treaty prevails in this
situation.54
47
Zuleeg (supra note 16), GYIL 20 (1977) p. 246 (256 with further references in footnotes 45 et seq).
48
Sinclair (supra note 1), p. 106 with further references in footnote 98.
49
See, for an overview, Zuleeg (supra note 16), GYIL 20 (1977) p. 246 (265-267).
50
See, in particular, the judgment of the ICJ in the North Sea Continental Shelf case, Judgment 20 February
1969, I.C.J. Reports (1969), p. 3 (41 et seq.).
51
Sinclair (supra note 1), p. 97.
52
See, e.g., the examples given by Volken, Konventionskonflikte (supra note 17), p. 303.
53
Even at the time of negotiations of the Vienna Convention, it was current State practice to bring amending
agreements into force as between those States willing to accept the amendment, while at the same time
leaving the existing treaty in force with respect to the other States parties to the earlier treaty, thus blurring
the distinction drawn in the Convention between “amendment” between all of the parties, and “modification”
between only some of them (see Sinclair (supra note 1), p. 106-107).
54
This will bring about State liability towards the parties to the other treaty (see Zuleeg (supra note 16), GYIL
20 (1977) p. 246 (262-268)).
15
47. Lastly, it is worth mentioning that, although Article 5 of the Vienna Convention
preserves usages developed within international organisations, one cannot speak of a
uniform practice developed in Hague Conventions to this effect. Whether a rule on the
relationship with other instruments is added in a new Hague Convention, and its possible
content, depend very much on the individual situation and the treaties in question.55
c) Conclusion
48. To sum up: In the absence of any rules established by the States parties to a
particular treaty, customary public international law in general and the varying practice
– depending on the subject matter of the treaty in question - developed within the Hague
Conference in particular56
do not add anything to the residual rules established by the
Vienna Convention. As far as the parties to the successive treaties are identical, the
general rules are largely identical with the rules embodied in the Vienna Convention.
Where no party identity is to be expected, this leaves us with the urgent need to include
appropriate clauses governing the relationship of the instruments in question because
public international law does not provide any default rule.
3. General principles of public international law
49. The principles embodied in the Vienna Convention that were discussed in the
paragraphs on customary international law are considered by others to form part of the
generally accepted principles of public international law: the principles of pacta sunt
servanda (see Article 26 of the Vienna Convention), lex specialis derogat legi generali,
and pactum tertiis non nocet. However, while the label attributed to them by some
authors – “general principles” or “customary international law” - may be different, the
content is not. Reference is therefore made to the content of these principles as just
described supra under 2.
B. How does European Community law fit into the rules described?
50. Public international law writers stress that, at the global level, secondary legislation
of the European Community (in particular directives and regulations) appears as a certain
type of “internal law” as opposed to international treaty law57
because it creates
harmonised rules applying to a sub-group of States parties to a global treaty which
replace those States’ national laws. And while the Court of Justice of the European
Communities (European Court of Justice – ECJ) strongly reaffirms community law’s
“particular” character, in relations with third States it also respects the precedence of
international law with regard to its own “internal” Community regime. Consequently, an
international treaty prevails over secondary Community law, no matter whether the
treaty is older58
or more recent59
than the Community law in question, unless explicitly
provided otherwise.
55
See, for a more detailed discussion, Volken, Konventionskonflikte (supra note 17), p. 303.
56
For an overview of history and development of disconnection clauses in Hague Conventions, see Volken
(supra note 22), p. 154. It was in the Hague Convention of 15 April 1958 on the Law Applicable to Transfer of
Title in the International Sale of Goods that, for the first time ever, a clause on the relationship with other –
existing and future (!) - instruments was introduced into a law-making convention on private international law
(Volken, ibid., p. 154 et seq.).
57
See Daillier / Pellet (supra note 3), p. 277 no 176; p. 281 no 181.
58
Daillier / Pellet (supra note 3), p. 283-284 no 181, mentioning that this is also reflected in the diplomatic
practice of the European Communities, e.g. in the declaration attached to the Warsaw Protocol of 1982 to the
Gdansk Convention of 1973 concerning fishing in the Baltic Sea, OJ EC No L 237 of 26 August 1983, p. 12. See
also ECJ, 12 December 1972, cases 21-24/72 (joint), International Fruit Cy, ECJR 1972, p. 1219 (No 11); ECJ
10 September 1996, case 61/94, Commission v. Germany, ECJR 1996-I, p. 3989 (Nos 39, 44, 45, 52); ECJ 16
June 1998, case 162/96, A. Racke GmbH & Co v. Hauptzollamt Mainz, ECJR 1998-I, p. 3655 (Nos 5, 7, 8, 29 et
seqq).
59
Daillier / Pellet (supra note 3), p. 283-284 no 181; see also implicitly ECJ 30 April 1979, case 181/73,
Haegemann v. Belgian State, ECJR 1974, p. 449.
16
III. LIMITS ESTABLISHED BY THE VIENNA CONVENTION FOR THE CONTENT OF A
DISCONNECTION CLAUSE
51. Many provisions of the Vienna Convention are expressed as residuary rules which
operate only unless the treaty provides otherwise. Thereby, a large degree of autonomy
is left to States to agree on specific rules governing the relationship of international
conventions,60
as long as the limits set by Article 30(4) and (5) and Article 41 of the
Vienna Convention are respected in cases where not all parties to the earlier treaty
become parties to the more recent one. While it is always possible to include a clause in
the more recent treaty giving priority to the earlier one, the more recent treaty may only
claim precedence under the conditions set out in Article 30(5) and Article 41 of the
Vienna Convention, as described above,61
unless the earlier treaty itself allows for
subsequent instruments to prevail (Article 30(2)). Where States do not comply with
these conditions, they may be liable for breach of the earlier treaty unless they include a
clause into the more recent treaty that temporarily suspends some of its effects and
obliges them to enter into negotiations with parties to the earlier treaty in order to
resolve the conflict.
IV. CONCLUSION
52. Whenever States are negotiating a new convention that might have an impact on
the application of an earlier treaty, it is advisable to include one or more clauses into the
new convention which define explicitly the relationship with other existing (and, if States
so wish, future) instruments.
53. To sum up what applies in the absence of a clause, and which kind of clause is
permissible in the new treaty: In general it can be said that the first step to be
undertaken is the interpretation of the treaties in question, and here the general
presumption is that the parties would want the more specific instrument to prevail. In
case all treaties concerned possess the same level of generality, individual provisions of
two different treaties would apply to the same factual situation and lead to incompatible
results, there is a presumption in favour of the lex posterior, which is slightly softened in
cases where not all parties to the earlier treaty become parties to the later one and as far
as the relations with them are concerned. The rights of those States who are only parties
to the earlier treaty need to be respected.
54. While it is easy to identify which is the earlier and which the later instrument,62
specificity can be a more difficult question: In the area of jurisdiction in particular,
specificity may be difficult to define where, e.g., one instrument is more specific ratione
materiae while the other is more specific ratione personae, ratione loci or ratione
temporis. And even the mere notion of ratione materiae is difficult to apply: would a
treaty dealing with patents only (i.e. with a certain subject matter, in both substance and
procedure) be more specific than a treaty dealing with jurisdiction based on choice of
court clauses (i.e. a – narrowly defined - procedural topic which could, however, cover
more than one subject matter)?
55. Therefore, one may be inclined to advise States parties to include explicit rules into
every instrument they negotiate. What applies in the absence of a clause, and which kind
of clause is permissible in the new treaty, depends first of all on whether all States
parties to the earlier treaty also join the later one.
60
See Article 30(2) Vienna Convention; Sinclair (supra note 1), p. 97-98.
61
Supra paragraph 27 et seqq.
62
According to Sinclair (supra note 1), p. 98; Zuleeg (supra note 16), GYIL 20 (1977) p. 246 (256), it is the
date of the adoption of the text and not that of its entry into force which is decisive.
17
A. All parties to the earlier treaty are party to the later treaty
56. Where this is the case, independent of whether the old treaty contains a clause on
the relationship with future instruments, in general States are in principle63
free to
change their will. Hence, also their freedom as to what clause to include into the new
treaty is unlimited.
57. In the absence of a clause, it is the presumption of the Vienna Convention that they
have terminated the old treaty and replaced it by concluding a new treaty on the same
subject-matter.
58. If treaty interpretation leads to the conclusion, however, that the States parties
wanted the old treaty to continue to apply, it would first of all depend on a clause in the
new treaty which one prevails. In the absence of a clause, the presumption is that the lex
posterior prevails in case of incompatibility. But any clause to a different effect would
equally permissible.
59. Where the two treaties in question do not relate to the same subject-matter within
the narrow meaning of the Vienna Convention, the presumption of termination of the
earlier treaty does not apply. Treaty interpretation will then lead to the conclusion that
the more specific treaty prevails in the absence of a clause. Otherwise, the parties are
free to agree on a different effect by inserting an appropriate clause into either treaty.
B. Not all parties to the earlier treaty become party to the later treaty
60. In cases where not all parties to the earlier treaty become party to the later treaty,
the solutions are the same to the extent that the parties to the earlier and later treaty
are identical. The application of successive treaties in their mutual relationship
therefore follows the rules described above. This means, in particular, that treaty
interpretation would suggest that the more specific treaty prevails. Where none of them
is more specific and the treaties in question do relate to the same subject-matter, treaty
interpretation can lead to the conclusion that the earlier treaty shall continue to apply
(e.g. where it is more generous), but in other cases the default rule of lex posterior will
lead to precedence of the later treaty in case of incompatible results produced by
individual provisions in the two treaties concerned, as applied to a particular factual
situation.
61. The application of the rules just mentioned, as well as the freedom of the parties to
the later treaty as to how to regulate the relationship between the two instruments in
question by including a clause into the later treaty is limited to some extent because the
rights of parties to the earlier treaty only have to be respected.
62. As far as those States, who are parties only to the earlier but not to the later treaty,
are concerned, they can still rely on the earlier treaty in their relations with any State
party to it, independent of whether the latter has subsequently entered into another
treaty on the same subject matter with some other States equally party to the earlier
treaty.
63. Moreover, Article 41 establishes some rules on the lawfulness of concluding a
subsequent treaty, thereby setting a framework of State responsibility in case of a
breach. The validity of the successive engagements, however, is not affected.
64. Where the old treaty contains a clause on the relation with future instruments, this
has to be respected in the relations with States parties to the earlier treaty only. Where it
does not contain any such clause, and States party to the later treaty would like it to
prevail in their mutual relationship over the old treaty, they may insert a clause to that
effect if the modification in question does not affect the enjoyment by other States
parties of their rights under the earlier treaty or the performance of their obligations, and
63
With the exception of jus cogens.
18
does not relate to a provision, derogation from which is incompatible with the effective
execution of the object and purpose of the earlier treaty as a whole.
65. One may conclude by stating that, even where at first sight, specificity and
generality seem to be easy to attribute to the various Conventions in question, things are
not that obvious. It has been described above that in most cases of overlap of scope of
the Judgments Convention and any instrument governing a specific subject matter
including, inter alia, rules on jurisdiction and enforcement for it, it would be difficult and
doubtful to try to define one as more specific than the other. This paper shows,
moreover, that even where the new instrument might be considered more specific, there
can be cases where the parties would be likely to wish the older instrument to continue
to apply between them.
66. The only conclusion to be drawn is that it is advisable to include explicit rules into
any international instrument that govern the relationship with other existing and future
instruments as well as any possibility for modification, where necessary (temporarily)
limiting the application of the new instrument in order to take account of the rights and
legally protected interests of States parties to an earlier instrument but not to the new
instrument. The latter requires a careful examination of the earlier treaty in question in
order to determine which rights and interests of States parties to those instruments
might be affected by the later instrument without a clause appropriately dealing with the
relationship of the two treaties.