Public International Law
H2 Sources of International Law
2.1 Introduction
Not a lot of important information.
2.2 Art. 38 of the Statute of the International Court of Justice
1 The Court, whose function is to decide in accordance with international law such disputes as are
submitted to it, shall apply:
a. International conventions (primary law)
b. International custom (primary law)
c. General principles of law (primary law)
d. Judicial decisions and teachings (secondary law)
Even though art. 38 is directed to the court, it’s considered general relevance.
First 3 sources are law creating – they create new rights & obligations. Last one is law identifying, it
merely applies the content of existing law.
2.3 Conventions
= treaty
- Is the only way states can enter into a formal legal relationship
- Legal basis = state consent treaty only creates legal obligations for the consenting states
- Pacta sunt servanda
Bilateral treaty= treaty concluded by 2 states issue of mutual interest between those states
Multilateral treaty = treaty concluded between larger groups of states law-making
Constituent treat = treaty that establishes an international organization
2.4 Custom
1. State practice followed as a general principle among states (objective)
a. Consistent repetition of particular behavior - so for a considerable period of time, states
have to have acted in a certain way
b. All state acts may be taken into consideration (physical and verbal) – verbal acts must be
public + internal documents and memoranda do not qualify
c. 3 elements:
I. Consistency – reasonable uniform / generally consistent
II. Duration – evolves slowly and gradually over time
III. Generality – unanimity not required, but practice should be the majority of
states. Very important whose interests are affected – it’s therefore important
which states participate.
d. A state can avoid being bound by it by persistently objecting. But only with emerging
rules – if it’s already come into existence, it can no longer be objected to.
2. Opinio juris accepted by those states as legally binding (subjective)
a. The acceptance of a given practice as law
b. Distinct between state practice out of habit/ convenience/ politeness vs. out of legal
obligation
Customary rule binds all states
Relationship between custom and treaty law
When a treaty codifies CIL, parties are both bound by the treaty and CIL, while non-parties are only
bound by CIL. Treaty-based obligations can also be identical to obligations in CIL when its content
develops into CIL.
,If the content of treaty and CIL is identical – they complement and reinforce each other – if not,
conflict can be avoided through interpretation. If interpretation doesn’t work, peremptory/jus
cogens norms always prevail. Otherwise, treaty prevails for the parties of the treaty. When
customary law develops later lex posterior later in time prevails.
2.5 General principles
Prevent the Court from being unable to decide a dispute due to a shortage of applicable law. Gap
fillers. Only goes for the general principles common to developed legal systems.
Most relevant one is equity (billijkheid). Another one is good faith – states must honestly in fulfilling
their international obligations. Another one is pacta sunt servanda. Elementary consideration of
humanity/no harm/ due diligence is also of importance- the greater the risk of harm to other states,
the greater effort the territorial state must exercise to prevent the harm from occurring.
2.6 Judicial decisions
Subsidiary source of law. – only binding to the parties of the case. For example decisions by the ICJ
are very important. Thin line between when a court identifies and when it develops law.
ICJ is not bound by its earlier decisions, but will try to maintain judicial consistency.
2.7 Scholarly contributions and the ILC
Not as important. Contributions of the International Law Commission (ILC) play a special role it’s
intended to be representative of all the principal legal systems of the world it selects topics and
makes proposals for draft conventions and codifications.
2.8 Unilateral statements
Unilateral statements can create obligations under international law. No requirements of form
both oral and written statements suffice.
Can be (just like with treaties) issued by:
- Heads of state
- Heads of government
- Ministers for foreign affairs
Nothing in the nature of a quid pro que (tegenprestatie) nor any subsequent acceptance of the
declaration of even a reply or reaction by other states is necessary for a unilateral statement to be
legally binding.
A unilateral statement needs to be:
- Clear
- In Specific terms
- Context need to be taken into account
- Circumstances need to be considered
For is to be legally binding.
2.9 Hierarchy of sources
Mostly horizontal. Apart from distinction between primary and secondary sources of law, all legal
sources generally carry same normative weight.
3 exceptions to normative equality in international law:
1. Peremptory/jus cogens norms
a. Art. 53 VCLT treaties/ unilateral statements are void if they conflict with jus
cogens
, b. Jus cogens is accepted and recognizes as a norm from which no derogation is
permitted
c. Substantive rules of conduct that prohibit what has come to be seen as intolerable
because of the threat is presents to the survival of states & their peoples & the most
basic human values.
d. Examples: prohibition against torture and genocide, the ban of slavery, prohibition of
aggression, ban of crimes against humanity and grave breaches of the laws of armed
conflict, prohibition of piracy, right to self-determination & prohibition of apartheid
and other forms of gross racial discrimination
2. Obligations erga omnes
a. Superior because they’re not owed to another state but the international community
as a whole
b. Can be invoked by any state, not just the one that is the immediate beneficiary of the
obligation
c. Jus cogens refers to substantive obligations that cannot be derogated from, erga
omnes is a procedural designation of a set of obligations that all states can invoke
3. Obligations under the UN Charter
a. Art. 103 stipulates that obligations of the Charter prevail when they conflict with
obligations under any other international instrument
b. States can’t be asked to disregard norms of jus cogens character
2.10 Non-binding commitments and the concept of ‘soft law’ instruments
States can make non-binding commitments – violation cannot lead to any legal consequences, but
the political price may be very high. If an instrument is legally binding can be found in the intention of
the parties.
When a legally non-binding instrument begins to plat a role in the creation of international law, it can
be referred to as soft law (opposite of hard law – legally binding sources).
Soft law instruments are not legally binding in themselves, but they may be legally relevant when
they assist in formulation or interpretation of one of the recognized legal sources. Soft law can be
evidence of state practice or opinio juris .
H3 The Law of Treaties
3.1 Introduction
Primary rules in the law of treaties are found in the 1969 Vienna Convention on the Law of Treaties
(VCLT). VCLT seeks to codify customary practices. VCLT applies to all types of written treaties
between states. Application of VCLT differs depending on the type of treaty.
3.2 The treaty as a concept under international law
A treaty is an international agreement governed by international law concluded by two or more
international subjects with treaty-making capacity.
VCLT is only about treaties between states. So while international organizations can be parties to a
treaty, the treaty will not be governed by the VCLT, but by the 1986 Vienna Convention.
Legal basis of a treaty is state consent – no one can force a state to enter into a legally binding
agreement + a treaty can only create legally binding obligations for the parties. (art. 34 VCLT)
Art. 26 VCLT treaty is binding upon parties
Art. 27 VCLT state must not invoke national laws as justification for a failure to perform treaty-
based obligations so state must comply with treaty even if it means that it breaches national laws.
Oral agreements can be treaties, but are not governed by VCLT (art. 3 VCLT).
, Title of a written instrument does not matter for it to qualify as a treaty it’s a treaty as long as it
intends to create rights and obligations. Intention of parties is most important when it comes to
determine if an instrument is a treaty the terminology and the form of the instrument may give
guidance to the party intend. The circumstances and the matter in which is delt with can also give
some guidance.
3.3 Authority to conclude a treaty
Art. 6 VCLT all states can conclude treaties, but not all representatives of states can.
Art. 7 VCLT which representatives can and can’t refers to concept of ‘full power’ (which is a
document that authorizes a state representative to negotiate and conclude treaties. Not all states
representatives need this ‘full power’
Art. 7 (2)(a) VCLT heads of state, heads of government and ministers for foreign affairs can
perform all acts that relate to the conclusion of the treaty without full powers.
Art. 7(2)(b) and 7 (2)(c) VCLT more limited authority for heads of diplomatic missions &
representatives accredited by a state to an international conference.
Art. 46(1) VCLT state may not invoke the fact that its consent to a treaty has been in violation of
its national laws as invalidating its consent unless the violation of the national law was manifest
(overduidelijk) and concerned a national rule of fundamental importance. Must be manifest in the
sense that it’s objectively evident to any state (art. 46 (2)) high threshold.
When a person with no authority to do so concludes a treaty (art. 8 VCLT) de staat kan besluiten
gebruik te maken van de mogelijkheid om de handeling van de persoon in kwestie te verloochenen
door vervolgens de handeling te bekrachtigen en daarmee zijn instemming met gebondenheid te
bevestigen
3.4 Treaties between states and international organizations
1986 VCLT regulates it, not yet in force, but exactly the same as 1969 VCLT.
3.5 Consent to be bound
Art. 11 VCLT consent may be expressed by a signature, an exchange of the instruments,
ratification, acceptance, approval or accession of by any other measure if so agreed. Consent is
necessary to be legally bound to the treaty. Today, it’s usually a signature (definitive signature).
Art. 15 VCLT state can give consent by accession, where it consents to be bound by a treaty
already negotiated and signed by other states in the following circumstances:
a. If the treaty provides for it
b. If it’s otherwise established that the negotiating parties were agreed that it should be
possible
c. If all parties have subsequently agreed that a state may express its consent by such means
Distinction between ratification and a signature:
Art. 14 VCLT sometimes consent doesn’t only require a signature, but a subsequent confirmation
by the state to allow a binding state a period of time before giving its binding consent. Often the
state needs approval of its national parliament.
Art. 82 VCLT the VCLT is subject to ratification
3.6 Entry into force – obligations in the interim period
State is not legally bound by a treaty (even when it consents) until in enters into force.