Tutorial 2
What are the sources of treaties?
The law of treaties is governed by two separate mechanisms: the 1969 Vienna
Convention on the Law of Treaties ("VCLT”) and customary international law. Since
the VCLT is mostly a codifcation of customary international law, these sources of law
overlap to a large degree.
A related difculty concerns the question of how customary provisions on the law of
treaties operate. There seems to be a general consensus exists that provisions
governing treaty interpretation, material breach and fundamental change of
circumstances are all part of customary international law.
The VCLT is considered to be a progressive document. In other words, when it was adopted in 1969,
some of its provisions were understood to be presumptive evidence of emerging rules. The scope of
the VCLT is limited, however.
First, the VCLT is solely applicable to treaties between states (Article 1 VCLT). It does not contain
provisions that are applicable to treaties concluded between states and international organizations,
or to treaties concluded between international organizations (which are governed by separate
conventions, as noted earlier).
Second, the VCLT does not contain any provisions on state succession to treaties (that is, when a
new successor state forms and replaces a predecessor state).
Third, treaties may be afected by various factors, such as situations of armed confict, but the VCLT
is silent on such efects.
What are treaties?
International law makes a general distinction between two types of treaties: bilateral and
multilateral. Bilateral treaties concern an international agreement between two contracting parties.
Multilateral treaties are agreements involving more than two state parties.
Article 2(1)(a) VCLT defnes a treaty as:
"'treaty' means an international agreement between States in written form and governed
by international law, whether embodied in a single instrument or in two or more related
instruments and whatever its particular designation.”
This defnition has several implications for the scope of applicability of the VCLT.
1. The VCLT only applies to treaties between states.
2. The VCLT only applies to written agreements (although, according to Article 3 VCLT, this
rule does not afect the applicability of other agreements).
3. Agreements between states which are governed by specifc domesticcmunicipal
law are excluded from the scope of the VCLT.
E.g. trade and commercial agreements, which are often governed by a particular state's
domestic law. Note: states are free to determine such arrangements among themselves.
International law does not require a particular form for a document to be classifed as
a treaty, as long as the parties have intended to create (international) legal
obligations. The intention of creating legal obligations signifes the crucial distinction
between formal international instruments (treaties) and informal international
instruments (such as 'memoranda of understanding').
International treaties usually follow a similar structure.
i. The frst part contains the title of the treaty, the state parties (mostly
abbreviated) and the subject of the treaty.
ii. The second part includes the preamble and the full listing of the parties to the
treaty. Also included in this part, is the rationale behind the conclusion of the
treaty. Furthermore, the goals pursued by the state parties to the treaty are
outlined.
iii. The third part of the treaty consists of the disposition, which concerns the main
provisions of the treaty. The disposition sets out the substantive obligations of the
parties.
iv. The fourth part typically includes fnal provisions, such as provisions governing
the end date of the treaty, the languages of the treaty and the date and place of
Literature: Chapter 3 – International Law, Part 9 & 22 – E-learning, 1
Cases: THE GABÇIKOVO-NAGYMARO PROEECT/ Tyrer vs. UK/ La Gran
, Tutorial 2
signature of the treaty. Some treaties contain annexes, which serve the goal of
interpreting the treaty.
The law of treaties is based on 2 basic principles.
1. Treaties need to be based on the free consent of States.
2. The other one is the most fundamental principles of the law of treaties, that
obligations under a treaty should be performed 'in good faith' -- also known as the
principle of pacta sunt servanda. The underlying reason for this principle is that
states possess full sovereignty and are in no way obliged to enter into treaty
obligations with each other. The fact that states enter into treaty relations out of their
free will indicates that they will perform their treaty obligations in good faith;
otherwise, entering into such obligations, in the frst place, would be irrational.
Art. 26 VLCT codifcation of the principle of good faith: "Every treaty in force is binding
upon the parties to it and must be performed by them in good faith.”
The principle of pacta sunt servanda consists of two main elements:
The treaty in force is binding upon the parties;
The treaty must be performed by the parties in good faith.
THE GABÇIKOVO-NAGYMAROOK PROOJECT (HHNNGAROY V. KLOVAKIAA
The International Court of Justice has confrmed the importance of the principle
of pacta sunt servanda in this case.
Relevant paragraphs 114, 142
How are treaties created?
The head of the state can perform acts relating to the conclusion of treaties, also the
heads of government, foreign ministers etc. art. 7 VCLT. However, the power of
ambassadors and representatives is limited to negotiating with the states or
organizations. Sometimes they have the full power to even sign.
Art. 8 VLCT if it’s clear that the representatives of States A and B can trust in each
other in saying who they are, then there is no particular need to present full powers.
The two main ways of expressing consent to be bound by treaties are signature and
ratifcation: the signature plays a double role. It expresses consent to be bound
(=political signifcance) and is a step towards ratifcation (signifying that agreement
on a text Is reached without expressing the state’s consent to be bound).
Art. 18 VCLT interim obligation: a state may not engage in behavior which would
‘defeat the object and purpose’ of the treaty concerned. This does not amount to a
full commitment just yet. This article creates a good faith obligation.
If states wish to apply to their agreement immediately, before de domestic
procedures have fnished, they can do so art. 25 VLCT: allows the provisional
application of treaties. Note: this does not mean that the treaty enters into force
quickly, but the treaty’s regime will be applied prior to its entry into force.
How are treaties interpreted?
One of the most common problems international courts and tribunals face is the
interpretation of treaties. Public international law has developed many rules and
techniques for treaty interpretation. These rules can be classifed in three main
categories:
A. Objective / textual approach: the interpretation is based on the actual text of the
agreement and the words chosen by the drafters are emphasised. This method of
interpretation considers the natural and ordinary meaning of the treaty text;
B. Subjective approach: this approach bases treaty interpretation on the intention of
the parties;
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