Introduction to International Law
Chapter 1
International law is a decentralized legal system. In history next to natural law
existed jus gentium (= law of people inferior to natural law). Consensual
theory = a state is only bound by the law if it gave consent for it. An issue
becomes of interest in more than one state in the following situations:
1. Colliding interests content: international law of coexistence (general).
2. Treaty form: international law of cooperation.
International law asserts its own supremacy over national law but doesn’t
preoccupy with how a state lives up to it > states choose how to implement
international on their own without interference of international itself. Forms of
implementation:
- Monism = international law is applied directly within the national legal
order: there is one big legal order that contains national and international
law (Kelsen: Grundnorm).
- Dualism = international law is applied domestically by translation into the
national legal order via transformation law: there are two separate legal
orders (national and international order).
Criticism of international law richer states control international law because
poorer states don’t understand international law enough to have an influence +
international law doesn’t contain feminism + international law is slow.
Misconception of international law primary purpose of international is to create
a just world (not true!) > purpose = the desire to uphold international order and
stability.
Chapter 2
International custom law = common use of interstate practice (consistent).
States are always bound by behavioural norms that are required for the
maintenance of peace. Relations between custom international law and treaty’s:
parallel obligations = a treaty crystallizes custom international law or codifies
an existing custom. Usually treaties prevail over customs because they are
deliberately made. If the treaty and customs create different obligations conflict
can be avoided trough interpretation, if not the prevail question arises: lex
posterior (subsequent law prevails) & lex specialis (detailed law prevails).
Exception to the absence of hierarchy:
- Peremptory norms (jus cogens) > art. 53 VCLT: no derogation
permitted – prohibition of intolerable acts because of the threat to the
survival of states and their people and the most basic human values.
- Obligations erga omnes: obligations owed to international community as
a whole breaches can be invoked by all states.
- Obligations under the UN charter (art. 103 & 25).
In international law there is no universal legislature or hierarchy or compulsory
jurisdiction and obligations can derive from multiple different sources. The
modern theory of sources is based on consent > must be expressed: (1) explicitly
, in treaties or (2) tacitly in custom accepted as law or as a general accepted
principle. Modern theory reflects in art. 38 of the ICJ Statute:
1. In disputes the court applies;
a. International conventions which are expressly recognized by the
contesting states = law creating.
The basis of treaties is consent (art. 34 VCLT) – effects in pacta sunt servanda.
Bilateral treaties include mutual interests, multilateral treaties have general
application and possess ‘law-making’ features. Constituent treaty = a treaty
that establishes an international organisation – sometimes competent to adopt
legal binding instruments.
b. International custom as evidence of an accepted general practice as
law = law creating.
Persistent objector rule = if a state persistently objects to a newly emerging
norm of international custom law during formation, then the objecting state is
exempt from the norm once it crystallises into law – this rule does not apply to jus
cogens-law. Customs bind all states, unless they persistently object or when it
arises regionally. Customs arise when particular behaviour is:
- A general practice among states (consistent repetition) > the objective
element of a custom (= state practice) – elements:
o Consistency > practice is reasonably uniform (Nicaragua).
o Duration > practice and opinio juris are created over time, but the
passage of time is not necessary for the formation of a new rule of
international custom law (North Continental).
o Generality > unanimity not required but it should include majority of
the states. Practices of states whose interest are specially affected are
particularly relevant (North Continental).
- Accepted by states as legally binding > the subjective element of a custom
(= the belief that the practice is legally binding) – element:
o Opinion juris sive necessitates = state practice is only legally
binding when accepted as law.
If a state defends its breach of international custom law by appealing to
exceptions or justifications contained within the rule, then it will confirm and not
weaken the rule and therefore will the breach not be justified – repeating
breaches will not form new international custom law as long as the opinion juris
on the breached law continues to exists (Nicaragua).
c. General principles of law recognized by civilized nations = law creating.
The presence of general principles avoids that courts can’t decide on a case due
to a shortage of applicable laws (= non liquet). General principles are primarily
gap fillers – examples: equity, good faith, pacta sunt servanda, no harm, due
diligence (requires a state to act regardless of whether the harmful acts are
lawful or not), res judicata (decision is final and binding all parties).
d. Judicial decisions (subject to art. 59) = law identifying.
The International Court of Justice (ICJ) is not bound by former judicial decisions
but strives consistency. The ICJ gives binding provisional measures to conflicting
Chapter 1
International law is a decentralized legal system. In history next to natural law
existed jus gentium (= law of people inferior to natural law). Consensual
theory = a state is only bound by the law if it gave consent for it. An issue
becomes of interest in more than one state in the following situations:
1. Colliding interests content: international law of coexistence (general).
2. Treaty form: international law of cooperation.
International law asserts its own supremacy over national law but doesn’t
preoccupy with how a state lives up to it > states choose how to implement
international on their own without interference of international itself. Forms of
implementation:
- Monism = international law is applied directly within the national legal
order: there is one big legal order that contains national and international
law (Kelsen: Grundnorm).
- Dualism = international law is applied domestically by translation into the
national legal order via transformation law: there are two separate legal
orders (national and international order).
Criticism of international law richer states control international law because
poorer states don’t understand international law enough to have an influence +
international law doesn’t contain feminism + international law is slow.
Misconception of international law primary purpose of international is to create
a just world (not true!) > purpose = the desire to uphold international order and
stability.
Chapter 2
International custom law = common use of interstate practice (consistent).
States are always bound by behavioural norms that are required for the
maintenance of peace. Relations between custom international law and treaty’s:
parallel obligations = a treaty crystallizes custom international law or codifies
an existing custom. Usually treaties prevail over customs because they are
deliberately made. If the treaty and customs create different obligations conflict
can be avoided trough interpretation, if not the prevail question arises: lex
posterior (subsequent law prevails) & lex specialis (detailed law prevails).
Exception to the absence of hierarchy:
- Peremptory norms (jus cogens) > art. 53 VCLT: no derogation
permitted – prohibition of intolerable acts because of the threat to the
survival of states and their people and the most basic human values.
- Obligations erga omnes: obligations owed to international community as
a whole breaches can be invoked by all states.
- Obligations under the UN charter (art. 103 & 25).
In international law there is no universal legislature or hierarchy or compulsory
jurisdiction and obligations can derive from multiple different sources. The
modern theory of sources is based on consent > must be expressed: (1) explicitly
, in treaties or (2) tacitly in custom accepted as law or as a general accepted
principle. Modern theory reflects in art. 38 of the ICJ Statute:
1. In disputes the court applies;
a. International conventions which are expressly recognized by the
contesting states = law creating.
The basis of treaties is consent (art. 34 VCLT) – effects in pacta sunt servanda.
Bilateral treaties include mutual interests, multilateral treaties have general
application and possess ‘law-making’ features. Constituent treaty = a treaty
that establishes an international organisation – sometimes competent to adopt
legal binding instruments.
b. International custom as evidence of an accepted general practice as
law = law creating.
Persistent objector rule = if a state persistently objects to a newly emerging
norm of international custom law during formation, then the objecting state is
exempt from the norm once it crystallises into law – this rule does not apply to jus
cogens-law. Customs bind all states, unless they persistently object or when it
arises regionally. Customs arise when particular behaviour is:
- A general practice among states (consistent repetition) > the objective
element of a custom (= state practice) – elements:
o Consistency > practice is reasonably uniform (Nicaragua).
o Duration > practice and opinio juris are created over time, but the
passage of time is not necessary for the formation of a new rule of
international custom law (North Continental).
o Generality > unanimity not required but it should include majority of
the states. Practices of states whose interest are specially affected are
particularly relevant (North Continental).
- Accepted by states as legally binding > the subjective element of a custom
(= the belief that the practice is legally binding) – element:
o Opinion juris sive necessitates = state practice is only legally
binding when accepted as law.
If a state defends its breach of international custom law by appealing to
exceptions or justifications contained within the rule, then it will confirm and not
weaken the rule and therefore will the breach not be justified – repeating
breaches will not form new international custom law as long as the opinion juris
on the breached law continues to exists (Nicaragua).
c. General principles of law recognized by civilized nations = law creating.
The presence of general principles avoids that courts can’t decide on a case due
to a shortage of applicable laws (= non liquet). General principles are primarily
gap fillers – examples: equity, good faith, pacta sunt servanda, no harm, due
diligence (requires a state to act regardless of whether the harmful acts are
lawful or not), res judicata (decision is final and binding all parties).
d. Judicial decisions (subject to art. 59) = law identifying.
The International Court of Justice (ICJ) is not bound by former judicial decisions
but strives consistency. The ICJ gives binding provisional measures to conflicting
