Public International Law
Week 1 – introduction
Chapter 2 – Sources of International Law
A source of public international law is:
1. A legal process, by which international norms are created, modified or annulled;
2. A location of the norms that are the result of these processes.
Identifying these sources in international law is harder than locating them in domestic law, and more
room for debate exists. There is no constitution and no legislature; public international law is
created by states, that happen to be the subjects also.
Public international law is mainly created through treaties (written) and customary law (unwritten).
The latter makes locating sources even harder.
Article 38 of the ICJ Statute is important in discussions about PIL sources. Provision one lists five
sources that the ICJ will consider when settling disputes. These are:
1. ‘conventions’ (treaties) (process + location);
2. Customary international law (process);
3. General principles of law (process);
4. Judicial decisions (location);
5. The teachings of the most highly qualified publicists of the various nations (location).
This list is not an official list of sources. It is an establishment of the competence or jurisdiction of the
ICJ.
Treaties are written agreements between states and/or international organizations. They can vary
greatly in form and function. States have a lot of freedom when it comes to making treaties; it can
contain whatever they want it to, as long as it doesn’t contravene peremptory norms of PIL (a.k.a.
jus cogens norms). These are norms that are hierarchically above other legal norms, and that no
state may deviate from. This will be discussed in Chapters 4 and 5.
Customary international law (customs) is unwritten; it’s hard to prove that it exists. Customs are
based on two factors:
1. There must be a general practice among states (objective). Can be found in the words and
actions of states (though omission and inaction can work too). The practice must be
sufficiently widespread and representative, as well as consistent.
Widespread/representative can mean every state is involved, but sometimes that is not the
case (e.g. coastal law/law of the sea). Consistency does not have to be perfect. States that
consistently oppose a custom before it is formed may not be bound when it comes to life.
2. There must be a form of acceptance by states that this practice is required by law (opinio
juris) (subjective). This can be challenging; a state is a legal person, not a natural one, and
can hardly hold beliefs. The beliefs of a state can be subtracted from its practice. The most
important distinction between an opinio juris practice and a ‘normal’ practice is the reason:
does the state see it as accepting a new legal rule, or as a habit/convenience/courtesy?
,The same rule can exist in both treaty law and customary international law. This relationship can be
found in three ways:
1. A treaty codifies a customary rule that already existed at the time of the treaty’s conclusion
(declaratory);
2. A treaty crystallizes a customary rule that was in the process of emerging at the time of the
treaty’s conclusion;
3. A customary rule comes to life because of a treaty rule.
General principles of law are unwritten legal norms of a broad character that play a gap-filling role in
the international legal field. When treaties and customs leave gaps, general principles can help the
courts reach their conclusions. This source can be found in two (sometimes contradictory) ways:
1. They may be understood as a source of law that’s derived from principles that are common
in all domestic legal systems and transposable to the international level. Unlike customs,
which are derived from practice among states, general principles are derived from practice
within states.
2. They may be understood as fundamental principles grounded in the international legal
system. It is based on international relations among states.
Decisions of International Organizations are not included in Article 38 of the ICJ Statute, but are still
widely regarded as a source of PIL. This proves that the list from Article 38 is outdated and
incomplete (though it is still the most comprehensible list out there). They are important because
some international organizations have organs that can make decisions that bind all member states.
An example is Article 25 of the UN Charter. Especially decisions with a legislative character (instead
of a specific, regional one) are important.
Unilateral declarations of states are another source of PIL not included in Article 38. It might be
legally binding if it’s published, depending on the content, the circumstances surrounding it, and the
reactions to it by other states.
‘Subsidiary means for the determination of international law’ refers to places where rules of PIL may
be found, as opposed to processes in which they are developed. Judicial decisions and teachings of
publicists are subsidiary means. They only serve to prove the existence of norms, not create them.
Thus far, this chapter has discussed binding norms. But non-binding norms also exist, and can play
an important role. They are not a source of PIL, though. They embody political or moral
commitments rather than legal obligations. An example are Guidelines or recommendations. There
are three main ways in which a non-binding instrument can contribute to the development of a
binding norm:
1. They may contribute to the development of a binding norm. E.g. is the UDHR giving rise to
the ICCPR and the ICSECR;
2. They may follow treaties, and serve as a means to expand or update treaty rules;
3. They may be distinct from any binding rules and have no relationship to them.
Chapter 3 – Subjects, Statehood, and Self-Determination
The international legal system has its own entities to which it applies (subjects). Sovereign states are
the main subjects of international law. Originally, they were the only entities that could be seen as
, subjects; nowadays, the amount has grown. For example, international (governmental)
organizations, individuals and peoples are also recognized as subjects.
A subject of international law is an entity that is capable of possessing rights, duties, and/or
competences under international law. Subjects are not necessarily identical in their nature or in the
extent of their rights. There is a distinction between subjects that have full legal capacity and
subjects that have partial legal capacity. States are the only entities with full legal capacity, meaning
they are the only ones to carry all of the rights/duties/etc. that international law can give them.
Entities with partial legal capacities will only have rights and competences that are necessary for the
exercise of their functions.
States are the most important and first subjects of international law. They are also the creators of
those laws.
International organizations play a prominent role as well. Examples of such entities are the EU or the
UN. International organizations are organizations that are established by a treaty or another
instrument governed by international law, and they possess their own international legal
personality. Their members are most often states. These organizations must be distinguished from
NGOs, as the latter are made up of private actors and not by means of treaties. NGOs can still play a
role in international law, though; they might be given observer status and might be heard.
Legal personality can be obtained explicitly (explicit provision in treaty/charter) or implicitly (for
example by looking at the intention of the founders and the functions of the organization).
Individuals used to not have any rights on the international level; only states could claim that
another state had been mistreating their nationals. This started changing after the Second World
War. International human rights law started emerging, giving individuals certain international rights,
and granting them access to special international courts. Individuals have also gained certain
obligations under international law. An example is international criminal law (which emerged at the
same time).
Groups of individuals, such as peoples, have also gained international rights. Peoples can be the
entire population of a state, but a state can also consist of multiple peoples. Indigenous people are
also an example of groups of individuals that hold special rights. Minorities count as well, although
they differ from the other two examples; the rights of minorities are individual rights, not collective
(meaning only individuals can make use of them, not groups as a whole).
Whether or not multinational corporations (MNCs) have legal personality is still unsure. They do
have certain economic rights under international law. It is increasingly argued that MNCs have
international obligations as well, in particular when it comes to respecting human rights and the
environment.
Because states are the main subjects of international law, it is important to know when something is
a state, how they are created, and how they cease to exist.
Sovereignty is a key feature of states and of great importance when it comes to international law.
It’s a sign of independence. Sovereignty has two dimensions: an internal one (state must have
highest authority within its territory; must have exclusive right to exercise public authority over
territory and people), and an external one (position in international community; state cannot be
submitted to another state’s authority without its consent (art. 2 UN Charter)).
Week 1 – introduction
Chapter 2 – Sources of International Law
A source of public international law is:
1. A legal process, by which international norms are created, modified or annulled;
2. A location of the norms that are the result of these processes.
Identifying these sources in international law is harder than locating them in domestic law, and more
room for debate exists. There is no constitution and no legislature; public international law is
created by states, that happen to be the subjects also.
Public international law is mainly created through treaties (written) and customary law (unwritten).
The latter makes locating sources even harder.
Article 38 of the ICJ Statute is important in discussions about PIL sources. Provision one lists five
sources that the ICJ will consider when settling disputes. These are:
1. ‘conventions’ (treaties) (process + location);
2. Customary international law (process);
3. General principles of law (process);
4. Judicial decisions (location);
5. The teachings of the most highly qualified publicists of the various nations (location).
This list is not an official list of sources. It is an establishment of the competence or jurisdiction of the
ICJ.
Treaties are written agreements between states and/or international organizations. They can vary
greatly in form and function. States have a lot of freedom when it comes to making treaties; it can
contain whatever they want it to, as long as it doesn’t contravene peremptory norms of PIL (a.k.a.
jus cogens norms). These are norms that are hierarchically above other legal norms, and that no
state may deviate from. This will be discussed in Chapters 4 and 5.
Customary international law (customs) is unwritten; it’s hard to prove that it exists. Customs are
based on two factors:
1. There must be a general practice among states (objective). Can be found in the words and
actions of states (though omission and inaction can work too). The practice must be
sufficiently widespread and representative, as well as consistent.
Widespread/representative can mean every state is involved, but sometimes that is not the
case (e.g. coastal law/law of the sea). Consistency does not have to be perfect. States that
consistently oppose a custom before it is formed may not be bound when it comes to life.
2. There must be a form of acceptance by states that this practice is required by law (opinio
juris) (subjective). This can be challenging; a state is a legal person, not a natural one, and
can hardly hold beliefs. The beliefs of a state can be subtracted from its practice. The most
important distinction between an opinio juris practice and a ‘normal’ practice is the reason:
does the state see it as accepting a new legal rule, or as a habit/convenience/courtesy?
,The same rule can exist in both treaty law and customary international law. This relationship can be
found in three ways:
1. A treaty codifies a customary rule that already existed at the time of the treaty’s conclusion
(declaratory);
2. A treaty crystallizes a customary rule that was in the process of emerging at the time of the
treaty’s conclusion;
3. A customary rule comes to life because of a treaty rule.
General principles of law are unwritten legal norms of a broad character that play a gap-filling role in
the international legal field. When treaties and customs leave gaps, general principles can help the
courts reach their conclusions. This source can be found in two (sometimes contradictory) ways:
1. They may be understood as a source of law that’s derived from principles that are common
in all domestic legal systems and transposable to the international level. Unlike customs,
which are derived from practice among states, general principles are derived from practice
within states.
2. They may be understood as fundamental principles grounded in the international legal
system. It is based on international relations among states.
Decisions of International Organizations are not included in Article 38 of the ICJ Statute, but are still
widely regarded as a source of PIL. This proves that the list from Article 38 is outdated and
incomplete (though it is still the most comprehensible list out there). They are important because
some international organizations have organs that can make decisions that bind all member states.
An example is Article 25 of the UN Charter. Especially decisions with a legislative character (instead
of a specific, regional one) are important.
Unilateral declarations of states are another source of PIL not included in Article 38. It might be
legally binding if it’s published, depending on the content, the circumstances surrounding it, and the
reactions to it by other states.
‘Subsidiary means for the determination of international law’ refers to places where rules of PIL may
be found, as opposed to processes in which they are developed. Judicial decisions and teachings of
publicists are subsidiary means. They only serve to prove the existence of norms, not create them.
Thus far, this chapter has discussed binding norms. But non-binding norms also exist, and can play
an important role. They are not a source of PIL, though. They embody political or moral
commitments rather than legal obligations. An example are Guidelines or recommendations. There
are three main ways in which a non-binding instrument can contribute to the development of a
binding norm:
1. They may contribute to the development of a binding norm. E.g. is the UDHR giving rise to
the ICCPR and the ICSECR;
2. They may follow treaties, and serve as a means to expand or update treaty rules;
3. They may be distinct from any binding rules and have no relationship to them.
Chapter 3 – Subjects, Statehood, and Self-Determination
The international legal system has its own entities to which it applies (subjects). Sovereign states are
the main subjects of international law. Originally, they were the only entities that could be seen as
, subjects; nowadays, the amount has grown. For example, international (governmental)
organizations, individuals and peoples are also recognized as subjects.
A subject of international law is an entity that is capable of possessing rights, duties, and/or
competences under international law. Subjects are not necessarily identical in their nature or in the
extent of their rights. There is a distinction between subjects that have full legal capacity and
subjects that have partial legal capacity. States are the only entities with full legal capacity, meaning
they are the only ones to carry all of the rights/duties/etc. that international law can give them.
Entities with partial legal capacities will only have rights and competences that are necessary for the
exercise of their functions.
States are the most important and first subjects of international law. They are also the creators of
those laws.
International organizations play a prominent role as well. Examples of such entities are the EU or the
UN. International organizations are organizations that are established by a treaty or another
instrument governed by international law, and they possess their own international legal
personality. Their members are most often states. These organizations must be distinguished from
NGOs, as the latter are made up of private actors and not by means of treaties. NGOs can still play a
role in international law, though; they might be given observer status and might be heard.
Legal personality can be obtained explicitly (explicit provision in treaty/charter) or implicitly (for
example by looking at the intention of the founders and the functions of the organization).
Individuals used to not have any rights on the international level; only states could claim that
another state had been mistreating their nationals. This started changing after the Second World
War. International human rights law started emerging, giving individuals certain international rights,
and granting them access to special international courts. Individuals have also gained certain
obligations under international law. An example is international criminal law (which emerged at the
same time).
Groups of individuals, such as peoples, have also gained international rights. Peoples can be the
entire population of a state, but a state can also consist of multiple peoples. Indigenous people are
also an example of groups of individuals that hold special rights. Minorities count as well, although
they differ from the other two examples; the rights of minorities are individual rights, not collective
(meaning only individuals can make use of them, not groups as a whole).
Whether or not multinational corporations (MNCs) have legal personality is still unsure. They do
have certain economic rights under international law. It is increasingly argued that MNCs have
international obligations as well, in particular when it comes to respecting human rights and the
environment.
Because states are the main subjects of international law, it is important to know when something is
a state, how they are created, and how they cease to exist.
Sovereignty is a key feature of states and of great importance when it comes to international law.
It’s a sign of independence. Sovereignty has two dimensions: an internal one (state must have
highest authority within its territory; must have exclusive right to exercise public authority over
territory and people), and an external one (position in international community; state cannot be
submitted to another state’s authority without its consent (art. 2 UN Charter)).
