The Law of Treaties

part I
prepared by Anna Szarek-Zwijacz PhD

Introduction
Codification of international law
Conclusion of treaties
Geneva Convention
 A treaty – definition
 It is an agreement between subjects of international law, creating
rights and obligations for them, regulated by international law.

 The term „treaty” is also defined in the doctrine as a consistent

declaration of will of two or more entities of international law that
has legal effects, i.e. creates rights and obligations effective in
international law.

 Each treaty is by its very nature binding (from the moment it enters
into force).

 As a rule, the provisions of a treaty are binding only for those

entities that have expressed their consent to be bound by it (parties
to a treaty).
 Types of treaties
• We can distinguish different types of treaties using various criteria,
e.g.:
• Bilateral treaties (concluded between only 2 entities) or multilateral
treaties (they are concluded on the regional level or on the
universal level - there are some treaties that almost all States are
parties to them).
• Concluded for an indefinite period or for a definite period of time.
• Embodied in a single document or in two or more related
documents.
• Concluded in a simple or complex way (consent to be bound by the
treaty is expressed by a State in one act or it’s a process).
What can be regulated by a treaty?
 Every field of cooperation between States (e.g. political,
military, economic, scientific cooperation, cooperation in
the field of environmental protection, territorial issues etc.).

 International organizations are also established through the

conclusion of a treaty that constitutes the statute of such an
organization (e.g. UN Charter).

 Of particular importance are multilateral treaties of a

general nature, codifying various
fields/problems/instruments of international law:
diplomatic law, consular law, humanitarian law, human
rights, law of the sea.
 Codification of International Law
• Codification means “the more precise formulation and systematization of
rules of international law in fields where there already has been extensive
State practice, precedent and doctrine” (Art. 15 of the Statute of the
International Law Commission).
• International law has not been yet codified as a whole system – we don’t
have any „Code of International Law” that would be binding for all States
(one document with all rules of international law), but the process of
codification is still in progress.
• Some fields of international law are (more or less) codified (diplomatic
law, humanitarian law), some not.
• Currently, the codification of international law is the role the UN
International Law Commission (ILC).
• On historical antecedents of the ILC please read from the ILC website:
https://legal.un.org/ilc/ilcintro.shtml
The UN building in Geneva, where ILC
meets (source: ILC website)
The session of ILC in Geneva (source: ILC
website)
 Codification in practice
 The UN International Law Commission (ILC) was created by the
UN General Assembly in 1949 for „promotion of the progressive
development of international law and its codification”.
 The Commission consists of 34 members which „shall be persons
of recognized competence in international law” (who possess
recognized competence and qualifications in both doctrinal and
practical aspects of international law).
 They are drawn from the various segments of the international
legal community, such as academia, the diplomatic corps,
government ministries and international organizations.
 All members of the Commission sit in their individual capacity
and not as representatives of their Governments.
Members of the ILC with members of
the Secretariat, July 2018 (source: ILC website)
 Codification of the law of treaties
• The rules of the law of treaties between States are included in
the Vienna Convention on the law of treaties (VCLT),
concluded at Vienna on 23 May 1969 (more than 50 years
ago!) during the diplomatic conference organized by the UN in
cooperation with the Austrian government.
• Entry into force of the VCLT: 27 January 1980.
• Parties: 116.
• We also have the Vienna Convention on the Law of Treaties
between States and International Organizations or between
International Organizations concluded on 21 March 1986 –
but still not yet in force.
Conference on Law of
Treaties Opens in Vienna
The UN Conference on the
Law of Treaties convened
at the Hofburg Palace in
Vienna on 26 March 1968
with some 300
representatives from 100
countries present (source:
UN website)
On the Vienna Convention
on he Law of Treaties and
its procedural history
please read the enclosed
materials (on TEAMS, in
pdf).
 The scope of the VCLT
 Vienna Convention 1969 regulates all main issues
concerning treaties between States:
- conclusion and entry into force of treaties
- observance, application and interpretation of treaties
- amendment and modification of treaties
- invalidity, termination and suspension of the operation of
treaties.
 according to art. 73 of VCLT, Convention does not regulate
any question that may arise in regard to a treaty from:
- a succession of States
- the international responsibility of a State
- the outbreak of hostilities between States.
 The „treaty” topics outside the VCLT
• Why VCLT does not regulate the issues listed in art. 73?
• Because each of them is extensive and complicated - it was necessary to regulate
each of them in a separate document.
• At the time when VCLT was being prepared, the work on the issue of State’s
responsibility was already underway, the work on succession of States in respect of
treaties was to be started, while the problem of the effects of armed conflicts on
treaties seemed to be non-codified at that time.
• Subsequently, the following documents were adopted in respect of these topics
(all of them was prepared by the ILC):
• In 1978 the Vienna Convention on Succession of States in Respect of Treaties was
adopted (on the basis on the draft prepared by the ILC).
• In 2001 the UN General Assembly adopted resolution: Articles on States
Responsibility for internationally wrongful acts (on the basis on the draft prepared
by the ILC) .
• In 2011 Draft articles on the effects of armed conflicts on treaties was adopted by
the ILC (but no further action was taken regarding this Draft…).
 A treaty – legal definition from the
VCLT
"Treaty means an international agreement concluded
between States in written form and governed by
international law, whether embodied in a single instrument
or in two or more related instruments whatever its
particular designation." (Art. 2(1)(a) VCLT)
It means, that the VCLT applies only to treaties:
- concluded between States (not with or between other
subjects of international law like international organizations,
Holy See etc).
- in written form.
The designation of a treaty does not matter: it could be:
treaty, convention, agreement, covenant, charter and
others…
 Capacity to conclude treaties
Article 6 VCLT. CAPACITY OF STATES TO CONCLUDE TREATIES
Every State possesses capacity to conclude treaties.

It does not mean, that every State may conclude every treaty.
Some treaties are open for participation for every State, some are only
for States, that fulfill the requirements established in the final
provisions of a particular treaty (e.g. a treaty is open only for the
member States of particular organization).
Bilateral treaties are in their very nature only for two particular States.
Multilateral treaties are mostly concluded by a particular
group/number of States which may provide (in the final provisions
of a treaty) the possibility of accession of other States to that treaty.
 Conclusion of a treaty
The process of concluding a treaty requires a few steps
to go:

1. Negotiations

2. Adoption (and authentication) of a text

3. Expression of the consent to be bound by a treaty

4. Entry into force by a treaty

 Negociations
• The process of concluding a treaty begins with negotiations
aimed at developing and adopting the text of a treaty.
• Of course, negotiations can start if States are interested in
concluding a particular agreement (the political decision on
the need to conclude a treaty is made).
• Negotiations can take place in an oral form during meetings of
representatives of States or in writing, through exchange of
correspondence. Often both forms are combined.
• In the case of multilateral international agreements, the
negotiations are conducted during diplomatic conferences
with the participation of representatives of States.
• Convening a conference is usually preceded by preparatory
works, often long-term, during which the preliminary draft is
being prepared, which is the basis for conducting negotiations.
Negotations of multilateral treaties
• Negotiations of multilateral treaties are much more
complicated - also technically - than bilateral, because they
require the consideration of the positions of many States.
That is why international organizations play often the role of
a forum for reaching an agreement.
• If the treaty is concluded within an international organization,
often the organ of that organization prepares a draft of that
treaty.
• Within the UN, it’s usually International Law Commission
who prepares the drafts, other UN bodies may also be
involved in the codification work (e.g. both Covenants on
Human Rights 1966 were prepared by the former UN Human
Rights Commission).
 Adoption of the text
Negotiations end with the adoption of the text of the treaty.
VCLT provides some rules in this regard:

Article 9 VCLT. ADOPTION OF THE TEXT

• 1. The adoption of the text of a treaty takes place by the
consent of all the States participating in its drawing up
except as provided in paragraph 2.
• 2. The adoption of the text of a treaty at an international
conference takes place by the vote of two thirds of the States
present and voting, unless by the same majority they shall
decide to apply a different rule.
 Consent to be bound
The crucial moment of the procedure of concluding a treaty is the
expression of the State’s consent to be bound by a treaty.
The relative VCLT provision states that:

Article 11 VCLT. MEANS OF EXPRESSING CONSENT TO BE BOUND BY A

TREATY
 The consent of a State to be bound by a treaty may be expressed by
signature, exchange of instruments constituting a treaty,
ratification, acceptance, approval or accession, or by any other
means if so agreed.

 The negotiating States shall choose the mean of expressing consent

to be bound by a particular treaty (it could be more than one for a
treaty, e.g. ratification or acceptance, although mostly it’s one).
 As a rule, the mean of expressing consent to be bound by a
particular treaty is provided in its final provisions.
 MEANS OF EXPRESSING STATE’S CONSENT

• The consent of a State to be bound by a treaty may by

expressed:
1. by „simple” means: only by signature of a treaty or
exchange of instruments constituting a treaty (diplomatic
notes) – after signing a treaty or exchange of diplomatic
notes no other actions/procedures are required, the State’s
consent is definitive;
2. by „two-stage” procedure: after signing a treaty on the
international level (or exchange of diplomatic notes), a
domestic procedure has to be carried out in a negotiating
State: ratification, acceptance or approval.
Signing of the Agreement on social security between the
Republic of Poland and the State of Israel (photo: P. Tracz)
Treaty between USA and
Republic of Poland
The last page of a
treaty wtih signatures
of US President
Donald Trump and
President of Republic
of Poland Andrzej
Duda.
(I made that photo in
the Treaty
Department of the
Ministry of Foreign
Affairs of Poland).
Exchange of instruments constituting a
treaty
The mean of concluding a treaty by exchange of instruments constituting a treaty can be used
only for bilateral treaties!
After bilateral negotiations one State is sending a diplomatic note to the other State proposing to
conclude an agreement (with the proposed text).
The second State is also sending its note to the previous State, in which it confirms that:
- it has received the note with the text (it copies that text in its note)
- it accepts the proposition of concluding an agreement.

Please read the example of the treaty concluded by exchange of instruments constituting a treaty
(diplomatic notes).

On TEAMS you’ll find the text of a treaty between Poland and Bosnia and Herzegovina concluded
in that way: Agreement on succession of Bosnia and Herzegovina in respect of treaties
concluded between the Republic of Poland and Socialist Federal Republic of Yugoslavia. The
first note was sent by the Embassy of Republic of Poland in Sarajevo on 3 November 2006,
the responding note was sent by the Ministry of Foreign Affaires of Bosnia and Herzegovina
on 22 December 2006.
 „Two-steps” means of expressing the
consent to be bound
The consent is expressed in two steps:
1. Firstly, a treaty has to be signed by the representatives of
the negotiating States (or the States have to exchange the
instruments constituting the treaty)
2. and than the consent to be bound has to be expressed in
a domestic procedure in every negotiating State:
- by ratification - the consent is expressed by the head of
State
- or by acceptance – the consent is expressed by the
government
- or by approval – which means, that a State may apply any
domestic procedure (it’s up to every particular State).
The last page of European Convention on the Protection of Human Rights and Fundamental Freedoms
1950
.

(source: CoE website)

Convention was signed and than has to be ratified by the States in their internal procedures according to its art. 59:
1. This Convention shall be open to the signature of the members of the Council of Europe. It shall be ratified.
Ratifications shall be deposited with the Secretary General of the Council of Europe. (…)
 Signing of the multilateral treaty
H.E. Mr. Muhammadu Buhari
President of the Federal Republic of Nigeria is signing the Paris Agreement 2015 to the UN Framework
Convention on Climate Change 1992.
This Agreement was open for signature at the United Nations Headquarters in New York from 22 April
2016 to 21 April 2017 and than subject to ratification, acceptance or approval by States.
 Between 1st and 2nd step
When a State has signed a treaty but has not yet ratified
(accepted or approved) it:

Article 18 VCLT. OBLIGATION NOT TO DEFEAT THE OBJECT

AND PURPOSE OF A TREATY PRIOR TO ITS ENTRY INTO
FORCE
A State is obliged to refrain from acts which would defeat
the object and purpose of a treaty when:
(a) It has signed the treaty or has exchanged instruments
constituting the treaty subject to ratification,
acceptance or approval, until it shall have made its
intention clear not to become a party to the treaty;
 Accession to the treaty
 It’s a mean for expressing the consent to be bound for a State, which
has not participated in the treaty’s conclusion (negotiation etc.) but
it want to join the treaty.

Article 15 VCLT. CONSENT TO BE BOUND BY A TREATY EXPRESSED BY

ACCESSION
The consent of a State to be bound by a treaty is expressed by
accession when:
(a) The treaty provides that such consent may be expressed by that
State by means of accession;
(b) It is otherwise established that the negotiating States were agreed
that such consent may be expressed by that State by means of
accession; or
(c) All the parties have subsequently agreed that such consent may be
expressed by that State by means of accession.
When can we establish that a treaty is already concluded?
(in the case, when the internal procedure is required)

Article 16 VCLT. EXCHANGE OR DEPOSIT OF

INSTRUMENTS OF RATIFICATION, ACCEPTANCE,
APPROVAL OR ACCESSION
• Unless the treaty otherwise provides, instruments
of ratification, acceptance, approval or
accession establish the consent of a State to be
bound by a treaty upon:
(a) Their exchange between the contracting States;
(b) Their deposit with the depositary; or
(c) Their notification to the contracting States or to
the depositary, if so agreed.
 Instrument (document) of ratification
(on the photo: document of ratification of the Protocol to the Consular Convention between
Great Britain and Poland signed by Her Majesty the Queen Elizabeth II – from Treaty Department
of Ministry of Foreign Affaires of Poland).
 The end of the internal procedures
(ratification, acceptance, approval)
• In the case of a bilateral treaty the instruments of ratification
(acceptance or approval) shall be exchanged between the
contracting States.

• In the case of multilateral treaty, a depositary should be designated

by the negotiating States. In that case, instruments of ratification,
(acceptance, approval or accession) shall be deposited with the
depositary.

• The depositary may be one or more States (in particular a State in

which the treaty was signed), an international organization or the
chief administrative officer of the organization (e.g. UN Secretary
General or Council of Europe Secretary General).
UN Depositary
H.E. Mr. Bogusław Winid
Ambassador Extraordinary
and Plenipotentiary
Permanent Representative of
the Republic of Poland
deposits to the UN Secretary
General the document of
ratification of the Republic of
Poland of the Arms Trade
Treaty 2013.
(with the Chief of Treaty
Section of the United Nations
Office of Legal Affairs, source:
UN website).
 Entry into force of a treaty
A treaty is binding for the States Parties after entering into force.

Article 24 VCLT. ENTRY INTO FORCE

1. A treaty enters into force in such manner and upon such date as it may provide or
as the negotiating States may agree.
2. Failing any such provision or agreement, a treaty enters into force as soon as
consent to be bound by the treaty has been established for all the negotiating
States.
3. When the consent of a State to be bound by a treaty is established on a date after
the treaty has come into force, the treaty enters into force for that State on that
date, unless the treaty otherwise provides.
4. The provisions of a treaty regulating the authentication of its text, the establishment
of the consent of States to be bound by the treaty, the manner or date of its entry
into force, reservations, the functions of the depositary and other matters arising
necessarily before the entry into force of the treaty apply from the time of the
adoption of its text.
 How to establish a date of entry into
force of a treaty?
• The rule is that a particular treaty provides when or
after fulfilling which requirements it enters into force.
• The treaties concluded only by signing usually come
into force „on the date of its signature” or after a
certain period of time after its signature (e.g. „30 days
after its signature”).
• The treaties concluded by exchange of instruments
constituting a treaty (diplomatic notes) usually come
into force „on the date of receiving a replay” (a note
with a replay of the second State)
 How to establish a date of entry into
force of a treaty?
• When after signing a treaty, a domestic procedure is
required, a treaty usually provides that:
1. Bilateral treaty comes into force after both
contracting States confirm the fulfillment of
domestic procedures (ratification, acceptance or
approval).
2. Multilateral treaty comes into force after a certain
number of negotiating States, specified by its
provision, express their consent to be bound and
deposit instruments of ratification (acceptance or
approval) by the depositary.
Examples of the final provisions of treaties regarding
entry into force (bilateral treaty)
 Examples of the final provisions of treaties regarding
entry into force (multilateral treaty)
• From the Vienna Convention on the Law of Treaties:

Article 84. ENTRY INTO FORCE

1. The present Convention shall enter into force on the thirtieth day following
the date of deposit of the thirty-fifth instrument of ratification or
accession.
2. For each State ratifying or acceding to the Convention after the deposit of
the thirty-fifth instrument of ratification or accession, the Convention shall
enter into force on the thirtieth day after deposit by such State of its
instrument of ratification or accession.
 Examples of the final provisions of treaties regarding
entry into force (multilateral treaty)
From the European Convention on the Protection on Human Rights and Fundamental Freedoms
1950:

ARTICLE 59
Signature and ratification
1. This Convention shall be open to the signature of the members of the Council of Europe. It
shall be ratified. Ratifications shall be deposited with the Secretary General of the Council of
Europe.
2. The European Union may accede to this Convention.
3. The present Convention shall come into force after the deposit of ten instruments of
ratification.
4. As regards any signatory ratifying subsequently, the Convention shall come into force at the
date of the deposit of its instrument of ratification.
5. The Secretary General of the Council of Europe shall notify all the members of the Council of
Europe of the entry into force of the Convention, the names of the High Contracting Parties
who have ratified it, and the deposit of all instruments of ratification which may be effected
subsequently.
 Use of terms during the procedure of
concluding a treaty
According to art. 2 VCLT:

(e) "Negotiating State" means a State which took

part in the drawing up and adoption of the text of
the treaty;
(f) "Contracting State" means a State which has
consented to be bound by the treaty, whether or
not the treaty has entered into force;
(g) "Party" means a State which has consented to
be bound by the treaty and for which the treaty is
in force;
 Status of treaties – bilateral
• Information on the status of bilateral treaties are
provided by the States Parties.
• They usually publish the texts of the treaties in
its official journals with official government
statements on the status of treaties.
• For example: in Poland the texts of treaties are
published in „Dziennik Ustaw” (treaties that were
ratified) or in „Monitor Polski” (other types of
treaties)
 Status of treaties – multilateral
• Current status of a multilateral treaty is provided by
the depositary of this treaty.
• The depositary informs on:
- when the treaty comes into force
- the number of signatories and parties to the treaty
- when and how a particular State expressed its
consent to be bound.
Basically, these information are most often provided on
the depositary's websites
 UN Secretary General as a
depositary
Anyone can check the current status of a particular treaty
on its depositary's website.
Please visit the website of the UN Depositary:
https://treaties.un.org/Pages/Home.aspx?clang=_en

UN Secretary General is designed the depositery of many

treaties, i.a. Vienna Convention on the Law of Treaties
1969:
https://treaties.un.org/Pages/ViewDetailsIII.aspx?src=TREA
TY&mtdsg_no=XXIII-
1&chapter=23&Temp=mtdsg3&clang=_en