• The question of sources is fundamental in any system of law.
• Law making is a continuous activity in any viable legal system.
• International legal system can accommodate the changing
requirements for regulation by: law making in new areas; and by
upgrading and refinement of existing laws, in the light of its law
• Considering the sources of international law it is realized that the
term “sources” implies many different, sometimes, conflicting
Article 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, whether general or particular, establishing rules
recognized by the contesting States;
(b) International custom, as evidence of a general practice accepted as law;
(c) The general principles of law recognized by civilized nations;
(d) Subject to the provisions of article 59, judicial decisions and the teachings of
the most highly qualified publicists of the various nations, as subsidiary means for
the determination of the rule of law.
• 2. This provision shall not prejudice the power of the Court to decide a case ex
aequo et bono, if the parties agree thereto.
• Treaties, custom, and principles of law, are
sometimes referred to as "primary sources",
• Judicial decisions and the teachings of
publicists are sometimes referred to as
“subsidiary” or "secondary sources" or
“evidence of international law rules”.
• George Schwarzenberger proposed the term
‘law creating process’ for primary sources i.e.
treaties, customs and general principles of
law; and ‘law determining agencies’ for
subsidiary means for determination of law, i.e.
judicial practice and doctrines.
• Herbert Briggs pointing “the confusion of the
term “sources” describes it as “the methods
or procedures by which international law is
• Oppenheim discussing its various meanings
differentiates between formal and material
sources: formal being the source from which
the legal rule derives its legal validity; and
material providing the substantive content of
that rule, e.g. the formal source of custom
may have its material source found in a treaty
• Discussing the difference between basis of law (common consent
of international community), causes of law (particular
circumstances in the development of communities, suggesting need
for a rule of conduct), and sources of rules of law (process by which
it first becomes identifiable as a rule of conduct with legal force and
from which it derives its legal validity).
• Sources of the rules of law distinct from the basis of the law, are as
a whole related to the basis of the legal system.
(Sir Robert Jennings, Sir Watts Arthur, Oppenheim’s International
Law, (Indian Branch: Peerson Education, 1996), 23.
• According to Salmond,
“a formal source is that from which a rule of law
derives its force and validity. The material sources, on
the other hand, are those from which is derived the
matter and not the validity of the law. The material
source supplies the substance of the rule to which the
formal source gives the nature and the law.”
(J. W Salmond, Jurisprudance, 7th ed. (London: Sweet
and Maxwell, 1924).
1) Article 38 1(a) of SICJ: ‘International Convention’
‘international conventions, whether general or
particular, establishing rules expressly
recognized by the contesting states’.
• Whenever an international dispute is decided,
its first application of the law is to find a treaty
application on the issue.
• In the presence of a treaty on related issue the
decision is based on it.
• Historically treaties are the second source of
• They were developed to give particularity to rules of
mutual conduct, than was provided by a custom.
• The word ‘convention’ means a treaty and whatever
the nomenclature is, the substance is the same: it is an
agreement made between two or more States or other
subjects of international law.
• Long before the establishment of UN and ICJ, in the
19th and 20th centuries, many treaties and
conventions played a great role in the development of
international law, such as Geneva Convention 1864,
Hague Conventions of 1899 and 1907, Treaty of
• After establishment of UN in 1945, treaty acquired the
most important mode of development of international
law, starting from Bill of Rights and under the United
Nations Treaty Series many thousand treaties have
been registered with the United Nations.
• According to Article 2 of the Vienna Convention
on the Law of Treaty 1969, ‘treaty’ is defined as:
“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
and whatever its particular designation”.
• Consent to a treaty may be expressed by
signature, ratification, or accession, and is
binding on the parties to it, who shall perform
the treaty in good faith by applying the maxim
pacta sunt servanda.
• Applicable to all types of treaty: multi lateral
or bilateral, universal or regional.
• Treaties which codify already existing customary law or
which have in fact attained the status of customary law
are binding on non-party states as well.
• Example: International Humanitarian Law (Geneva
Conventions and Hague Conventions), Genocide
Conventions, Convention Against torture (CAT)1984,
Vienna Convention on Diplomatic Relations, 1961, UN
Charter 1945 and Universal Declaration of Human
Rights (UDHR) 1948.
• Treaties could be a direct source of
international law or reflective of a customary
or general principles of law as evidence.
• International treaties could be a) law making
treaties or b) treaty contracts.
a) Law- making Treaties
• Law-making treaties are those agreements whereby states elaborate their
perception of international law upon any given topic or establish new rules which
are to guide them for the future in their international conduct.
• Such lawmaking treaties, of necessity, require the participation of a large number
of states to emphasize this effect, and may produce rules that will bind all.
• Law making treaties could be either enunciating rules of universal international
law, e.g, Un Charter, or one laying down general principles such as Geneva
Conventions on the Law of the Sea (1958 and 1960) or Vienna Convention on the
Law of Treaties, 1969.
(L.N. Tandon and S .K. Kapoor International Law,(Lahore: Mansoor Book House,
2010), 101-102, and Malcolm N. Shaw, International Law,( United Kingdom:
Cambridge University Press 2008), 95).
• Provisions of Law-making treaty are directly
the source of international law.
Starke, J.G.(Joseph Gabriel), An Introduction to
International law , (London: Butterworths,
b) Treaty Contracts
• Treaties dealing with special agreements
between parties to the contract.
• The provisions of such treaties are binding only
on the parties to the treaty.
• Such treaties also help the formation of
international law through the operation of the
principles governing the development of
– A treaty is an agreement between states, between
states and international organizations, or between
international organizations, that is binding under
international law (something binding under the laws
of one state is not international)
– Treaties are binding and legally enforced upon the
parties to it
– Treaties can be bilateral or multilateral
2) Article 38 1 (b) SICJ: ‘International Custom’
• ‘international custom, as evidence of general
practice accepted as law’.
• According to the Right of Passage Case:
Portugal v. India (1960), there are 2 types of
Customary rules binding upon international
community as a whole.
Applicable to a group of states or just 2 states in
the relations inter se.
• “Custom is the oldest and the original source
of international law as well as law in general.”
(Jennings, Arthur, Oppenheim’s International
• ‘It is the foundation stone of the modern law
of the nations’.
(Dixon Martin, International Law, (London:
Blackstone Press Limited, 2000), 28).
• ‘When a usage receives the general
acceptance or recognition by the states in
their mutual relations, it is understood that
such habit or usage has become right as well
as obligation of the states; it becomes a
(Tandon and Kapoor, International Law, 95).
• However, although a custom is widely
followed, it does not make it a rule of
international law unless it is accepted by the
states as legally binding in order to be
considered rules of international law, referred
to as opinio juris.
• Two essential elements:
a) practice, and
b) opinio juris.
• In Advisory Opinion on the Use of Nuclear
Weapons (1996), it was held that
‘no rule can be created on opinion juris
without state practice’.
• Judicial application of international custom is
understood in the ICJ rulings in S.S. Lotus case,
North Sea continental Shelf case, Nicaragua v.
Unites States of America case, West Rand
Central Gold Mining Company Ltd. v. R.,
Asylum case between Columbia and Peru,
Advisory Opinion On use of Nuclear Weapons
• In S.S. Lotus case (Turkish International Water)
PCIJ series A, No 10, (1927), it was held that
“a new rule of customary international law
cannot be created unless both these elements
as discussed are present.”
• In North Continental shelf case, ICJ Rep. 1969, at p.3,
p.44, it was held
“not only must the acts concerned be a settled
practice, but they must also be such or be carried out
in such a way as to be evidence of a belief that this
practice is rendered obligatory by the existence of a
rule requiring it, the states concerned must feel they
are conforming to what amounts to a legal obligation.”
(Cited by Jennings, Arthur Oppenheim’s International
• In Nicaragua v. Unites States of America case (1986), it
was held that
“in order to deduce the existence of customary rules
the court deems it sufficient that the conduct of the
states in general should be consistent with such a rule
and that instances of state conduct inconsistent with a
given rule should have been treated as breach of that
rule not as indication of the recognition of a new rule.”
(Shaw, International Law,78).
• In West Rand Central Gold Mining Company Ltd. v. R.
(1905) 2K.B. 291, a test regarding the general
recognition of custom was laid down.
• The court ruled that for a valid international custom it
is necessary that it should be proved by satisfactory
evidence that the custom is of such nature that it has
received general consent of the States and no civilized
State shall oppose it.”
(Cited in Tandon and Kapoor International Law, 99).
• Asylum Case: Columbia v. Peru (1950)
• ICJ described custom as ‘ a constant and uniform usage,
accepted as law’.
• Meaning: those areas of state practice which arise as a
result of a belief by states that they are obliged by law to
act in the manner described.
ICJ held that: ‘where a local or regional customs is alleged,
it is the duty of the proponent to prove that this custom is
established in such a manner that it has become binding on
the other party’.
• Although an international court in the first
instance is bound to consider an applicable
treaty provisions, in case of doubt, it is
interpreted against the customary rule.
• In case of any conflict of a treaty provision
with a jus cogen, it will prevail over the treaty.
3) Article 38 1 (c) SICJ : General principles
of Law recognized by the civilized nations
• Third source of international law.
• Most modern jurists accept that ‘general
principles of law’ are principles of law common to
all national legal systems, in so far as they are
applicable to relations of States.
(Peter Malanczuk , Akehurst’s Modern
Introduction to International Law, (London:
George Allen & Unwin , 1997); Dixon, Textbook
on International Law, Cassese, Anthonio,
International Law, (Oxford University Press, 2001)
• ‘Principles’ refer to
a) certain principles and procedure
b) principles of good faith
c) principles of res judicata
• They also mean rules or standards which we find repeated in much
the same form in the developed systems of law, either due to
common origin, or expressing a necessary response to certain basic
needs of human associations.
• Examples are: the rules of pacta sunt servanda, that contracts must
be kept; reparation must be made for damage caused by fault; the
right of self defense for the individual against attack on his person,
family, or community against clear and present danger; for one’s
own cause no one can be a judge; and that the judge must hear
(J.E.S. Fawcett, The Law of Nations,( London, 1968), 24-25).
• The most important general principle,
inherent in international legal rules, is that of
good faith, enshrined in the United Nations
Charter, and its elaboration in the Declaration
on Principles of International Law Concerning
Friendly Relations and Co-operation among
States adopted by the General Assembly in
resolution 2625 (XXV), 1970.
• Article 2(2) United Nations Charter: ‘all Members, in order to
ensure to all of them the rights and benefits resulting from
membership, shall fulfill in good faith the obligations assumed by
them in accordance with the present Charter’.
• Declaration on Principles of International Law Concerning Friendly
Relations and Co-operation among States adopted by the General
Assembly in resolution 2625 (XXV), 1970, where it referred to the
obligations upon states to fulfill in good faith their obligations
resulting from international law generally, including treaties. It
therefore constitutes an indispensable part of the rules of
international law generally.
(described by Shaw, International Law, 104)
• The main objective of inserting the third source in
Article 38 is to fill in gaps in treaty and customary
law and to meet the possibility of a non liquet.
• Non liquet means the possibility that a court or
tribunal could not decide a case because of a
‘gap’ in law.
• Example, the ICJ applied the doctrine of non
liquet in the Nuclear Weapons case, Advisory
Opinion, (1997) 35 ILM 809 and 1343.
• Examples of cases where judicial applications
of general principle of law can be found:
Arbitration Tribunal in the AMCO v. Republic
of Indonesia case, Nuclear Tests case,
Chorz´ow Factory case in 1928, Barcelona
Traction case (1970) and Administrative
• Arbitration Tribunal in the AMCO v. Republic of
Indonesia case, where it was stated that:
‘the full compensation of prejudice, by awarding
to the injured party the damnum emergens and
lucrum cessans is a principle common to the main
systems of municipal law, and therefore, a
general principle of law which may be considered
as a source of international law’.
‘One of the basic principles governing the creation and
performance of legal obligations, whatever their source, is
the principle of good faith. Trust and confidence are
inherent in international co-operation, in particular in an
age when this cooperation in many fields is becoming
increasingly essential. Just as the very rule of pacta sunt
servanda in the law of treaties is based on good faith, so
also is the binding character of an international obligation
assumed by unilateral obligation’.
(Nuclear Test case (Australia v France), Judgment of 20
December 1974, ICJ Rep. 1974, 268, para, 46).
• In the Chorz´ow Factory case in 1928, PCIJ, Series A, No. 17, 1928, p. 29; 4
AD, p. 258, which followed the seizure of a nitrate factory in Upper Silesia
by Poland, the Permanent Court of International Justice declared that :
‘it is a principle of international law and even a general concept of law,
that any breach of an engagement involves an obligation to make
• The Court also regarded it as: a principle of international law that the
reparation of a wrong may consist in an indemnity corresponding to the
damage which the nationals of the injured state have suffered as a result
of the act which is contrary to international law.
(cited by Shaw, International Law).
• Eastern Carelia Case (11923)
‘one of the fundamental principles of
international law is independence of state’.
• In Barcelona Traction Case (1970), for
example, the Court has acknowledged the
concept of the ‘limited liability company’ to be
found in domestic law systems.
• In the Administrative Tribunal case, the Court dealt
with the problem of the dismissal of members of the
United Nations Secretariat staff and whether the
General Assembly had the right to refuse to give effect
to awards to them made by the relevant Tribunal.
• In giving its negative reply, the Court emphasized that:
“according to a well-established and generally
recognized principle of law, a judgment rendered by
such a judicial body is res judicata and has binding
force between the parties to the dispute.”
4) Article 38 1 (d) SICJ: judicial decisions and
the teachings of the most highly qualified publicists of
the various nations.
‘Subject to the provisions of article 59, judicial
decisions and the teachings of the most highly
qualified publicists of the various nations, as
subsidiary means for the determination of the
rule of law’.
a) Judicial Decisions
• Judicial decisions do not make law but are
declaratory of pre-existing law qualifying
them as, indirect, law identifying or material
sources of law.
• Article 59 of the Statute of the International Court of
Justice, provides that:
‘decisions of the courts have no binding force, except
for the parties and in respect of the case concerned’.
• This provision shows that:
a) Decision of the ICJ has no binding authority.
b) ICJ does not make law.
• In practice, the ICJ will follow the previous
decisions so as to have judicial consistency, or
if it does not follow, the court will distinguish
its previous decisions from the case actually
(case: Interpretation of Peace Treaties, 1950).
• Contrary to the Common Law, the doctrine of
precedence does not exists in international
law, still we find that the Court itself in its
decisions, the states in their disputes and legal
writers in their scholarly works quote
judgments of PCIJ and ICJ as an authority.
• Thus even as a subsidiary source, judicial
decisions are important in the determination of
the existence of the legal rules and their content.
• A unanimous, or almost unanimous, decision
plays an important role in the progressive
development of the law, e.g. the decisions and
advisory opinions in the Reparation, Genocide,
Fisheries, and Nottebohm cases have had decisive
influence on general international law.
• Reparations for Injuries Suffered in the Service of
the United Nations case, (1949) ICJ Rep. 174,
• Reservations to the Genocide Convention case,
(1951) ICJ Rep. 15.
• Anglo-Norwegian Fisheries case, (1951) ICJ Rep.,
• Nottebohn case, (1955) ICJ Rep. 4.
b) ‘the teachings of the most highly
qualified publicists of the various nations’.
• With marked influence in the history of
international law from 16th-18th centuries
writers such as Gentili, Grotius, Pufendorf,
Bynkershoek and Vattel were considered
authorities in determining the scope, form
and content of international law; today juristic
writings are considered a material or
evidential source only.
• Textbooks are used as a method of discovering
what the law is on any particular point rather
than as the source of actual rules, and the
writings of even the most respected
international lawyers cannot create law.
Other Sources of PIL
• Article 38 of ICJ is not exhaustive statement
for describing sources of international law as
since its formulation in 1945, many changes in
the international community have taken place.
• Other Sources which have contributed and are considered
important in the constant development of the international
law include: declarations of Security Council, binding on
member states; Non-legally binding instruments, often
referred to as “soft law”, such as declarations, resolutions,
and recommendations adopted by the UN General
Assembly and various international organizations; and
conferences, International comity and morality; and equity,
(a) in the sense of considerations of fairness and
reasonableness,(b) in a more strictly legal sense regarded
as forming part of certain rules of law, general principles of
law, or (c) in the sense of Article 38 (2) of ICJ, which
empowers the court , if the parties to a case agree, to
decide the case ex aequo et bono.
a) Declaration of Security Council
• Security Council has the competence to adopt
resolutions under articles 24 and 25 of the UN
Charter binding on all member states of the
b) Soft Law
• According to Professor Antonio Cassese, soft
law instruments, short of reaching full
consensus of view to agree for a binding
commitment, have three main common
features; 1) indicative of modern trends, 2)
matters of new concern for international
community, and 3) having economic, political
or other factors.
c) Resolutions of UN General Assembly
• Resolutions of the General Assembly are generally not legally binding and
are merely recommendatory, putting forward opinions on various issues
with varying degrees of majority support.
• This reflects the intention that the GA was to be basically a parliamentary
advisory body with the binding decisions being taken by the Security
• Nowadays, the situation is somewhat more complex. The Assembly has
produced a great number of highly important resolutions and
declarations, which have definite impact upon the direction adopted by
modern international law.
• The manner of states’ voting and the explanations given upon such
occasions reflect evidence of state practice and states’ consideration of
• The Court in the Nicaragua case tentatively expressed the view that the
opinio juris requirement could be derived from the circumstances
surrounding the adoption and application of a General Assembly
• It noted that the relevant opinio juris may, though with all due caution, be
deduced from, inter alia, the attitude of the parties [i.e. the US and
Nicaragua] and the attitude of States towards certain General Assembly
resolutions, and particularly resolution 2625 (XXV) entitled ‘Declaration on
Principles of International Law concerning Friendly Relations and Co-operation
among States in accordance with the Charter of the United
(ICJ Reports, 1986, pp. 14, 99–100; 76 ILR, pp. 349, 433–4. Shaw,
International Law, 6th ed., 115).
d) International Organizations
• Over the 50 years after establishment of UN
and ICJ the most significant change in the
international community has been the
increased number of international
organizations and their significant role.
• Contribute to the formation of international
law, but indirectly.
f) International Comity and Morality
• Mutual relations of states are based on the principle of
comity and morality, rules which are not legally binding.
• Oppenheim gives the example of exemption of custom duty
granted to diplomatic envoys not as rule of international
law but as a rule of comity.
• Though comity is not a source of international law but
many a rule which formerly was a rule of international
comity only is nowadays a rule of international law.
(Jennings, Arthur, Oppenheim’s International law, 51).
• In the Barcelona Traction case (I.C.J. rep.
(1970), pp. 3,5, Sir Gerald Fitzmaurice
emphasized the need for a body of rules and
princiles of equity in the field of international
(Cited by Tandon and Kapoor, International
• The tribunal in the Rann of kutch arbitration held
that since equity formed part of international law
the parties were free to present and develop
their case with reliance on principle of equity.
• In such case equity requires legal character and is
applied not just as equity but as part of a legal
(Jennings, Arthur, Oppenheim’s International law,
h) Ex aequo et bono
• Ex aequo et bono: Latin term meaning "according
to the right and good" or "from equity and
• In the context of arbitration it refers to the power
of the arbitrators to dispense with consideration
of the law and consider solely what they consider
to be fair and equitable in the case at hand.
• ICJ has not yet given any judgment on the basis of
Article 38 (2).
i) State Papers, State Guidance and
• State papers exchanged during their mutual
diplomatic relations, state guidance for their
officers by their legal advisors, and judicial
reason through which principles are
discovered, could also be some other
subsidiary sources of international law.
• Article 38 is quite comprehensive in detailing major
formal and material sources of international law;
describing treaties, customs and general principles as
the major formal sources; providing general principles
as filling the gaps between customary rules and
treaties; and as subsidiary means providing judicial
decisions, which has now become a trend setting
evidence of immense value in determining the rules of
law, reflected in the teachings of the most highly
qualified publicists of the various nations which are
also described as subsidiary means, under the same
provision of the article.
• Judicial decisions however, will remain subsidiary as they
are fact specific and apply to the states concerned only.
• Subject to states’ concerned consent provision of equity is
also available in Article 38 (2) SICJ.
• However, the article cannot be considered totally
exhaustive in its provisions as other subsidiary means
provided in the preceding paragraphs are also contributive
in the complexed ever growing matters of international
community, in the spheres of public as well as private
• Since treaties have become a major source of international law,
considering the statement of international conventions and treaties
as the only considerable way in creation of international law, it is
quite clear from the above discussion, that it is not correct.
• It is also concluded that one of the distinctive feature of
international law making is the absence of any hierarchy between
custom and treaties as sources of law, with even more force of jus
cogens or peremptory norms of general international law,
prohibition against torture or non refoulement for instance.
• States may not derogate from jus cogens through treaties or
customary rules even. It follows that jus cogens is hierarchically
superior to all the other rules of international law.