deserve assistance for their development and need to have differentiated
treatment.
Is there any hierarchy in
international law?
The international legal system operates on a horizontal structure of
authority, in which the subjects of international law are equal and bound by
legal rules only if they express their consent. Hence, the adoption of treaties
is dependent upon State consent, whereas custom requires consistent
practice by some States and the explicit or tacit consent of others. It is not
surprising, therefore, that the formal sources of international law (treaties,
custom, and general principles) are not set out in hierarchical order. This,
however, does not mean that there is no hierarchy of norms in international
law.
Jus cogens norms
In 1960, the ILC fuelled the discussion on the distinction of norms. In
drafting the VCLT, the members of the ILC put forward the idea that not all
rules of international law have the same juridical value, there being certain
norms from which no derogation should be allowed. These peremptory
norms of international law (jus cogens) reflect the most fundamental values
of international society and thus stand at the apex of the normative pyramid
of the international legal system. This theoretical construction was laid
down in Art 53 VCLT, stipulating that:
a treaty is void if, at the time of its conclusion, it conflicts with a peremptory norm of general
international law. For the purposes of the present Convention, a peremptory norm of general
international law is a norm accepted and recognized by the international community of States
as a whole as a norm from which no derogation is permitted and which can be modified only
by a subsequent norm of general international law having the same character.
Nonetheless, the ILC was careful not to lay down an exhaustive list of such
jus cogens norms, as its purpose was to produce an open-ended list of such
norms that would change, depending on the exigencies of international
society. Jus cogens norms differ from all other international legal rules,
conveniently called jus dispositivum, in the fact that jus cogens can never be
altered, even by consent between certain States. Thus, while two States may
deviate from a rule of jus dispositivum, like the prohibition of fishing within
the territorial waters of foreign States, and conclude an agreement allowing
it, this cannot occur in respect of the prohibition of genocide. Such
agreement would be null and void. What are these jus cogens norms?
Having in mind their fundamental significance for the international legal
order, such norms should include the prohibition of aggression, the
prohibition of genocide, and the protection of fundamental provisions of
international human rights and humanitarian law, such as the prohibition of
torture, slavery, apartheid, etc. Even so, the ICJ has been extremely reticent
in enunciating the existence of such norms. First, it insinuated that the
prohibition of the use of force may be a jus cogens norm in Military and
Paramilitary Activities in and against Nicaragua (Nicaragua v USA)
(1986). After many years, the Court did officially acknowledge a norm as
jus cogens: in Armed Activities on the Territory of the Congo (New
Application: 2002) (Democratic Republic of the Congo v Rwanda) (2006),
the Court accepted that the prohibition of genocide was part of jus cogens.
It made a similar finding in Questions Relating to the Obligation to
Prosecute or Extradite (Belgium v Senegal) (2012) in respect of the
prohibition of torture. Notably, in 2015, the ILC decided to revisit the issue
of jus cogens and included it in the list of the topics currently under
consideration.
Erga omnes obligations
Closely related, but not identical, to jus cogens is the notion of obligations
erga omnes, ie international obligations that are not contractual in nature,
but are owed to the international community as a whole. For example, the
Court in East Timor (Portugal v Australia) (1995) recognized the principle
of self-determination as an obligation erga omnes. The latter term,
however, finds its provenance in the landmark dictum of the ICJ in the
Barcelona Traction case in 1970 (see ‘Key cases’), in which the Court drew
‘an essential distinction’ between obligations owed to particular States and
those owed ‘towards the international community as a whole’. The
distinctive feature of such obligations is that its performance does not
concern only the State to which the obligation is owed; for example, in the
context of a bilateral investment treaty, the only State that does care about
the breach of an obligation under the treaty would be the other contracting
party. On the contrary, obligations erga omnes are of such a nature that all
States have a legal interest in their performance. Hence, in the event of a
breach of such obligation, all States are entitled to raise the issue before
political organs or are considered to have the requisite legal interest and
invoke the responsibility of the wrongdoing State before the ICJ.
Specifically, the ILC Articles on State Responsibility (2001) provide for
such invocation of responsibility by non-injured States in case of a breach
of an obligation erga omnes or erga omnes partes, which, according to the
ILC, pertain to ‘collective obligations’, ie obligations that apply between a
group of States and have been established in some collective interest, such
as the environment or security of a region or human rights law. This was
also affirmed by the ICJ in the Questions Relating to the Obligation to
Prosecute or Extradite (Belgium v Senegal) (2012) and Application of the
Convention on the Prevention and Punishment of the Crime of Genocide
(Gambia v Myanmar), Provisional Measures Order (2020).
On the one hand, it is logical that all jus cogens norms set out obligations
erga omnes. For example, all States have a legal interest in the observance
of the prohibition of genocide or torture.
On the other hand, obligations erga omnes do not spring exclusively from
jus cogens norms. In other words, a State may assume an obligation, which,
even if not of peremptory character, is assumed erga omnes or towards a
group of states for their collective interest, for example, for the protection
of environment (‘oblgations erga omnes partes’). For example, in Nuclear
Tests (New Zealand v France) (1974), the statement of the French
President that France would not engage in any atmospheric nuclear tests
conducted in the South Pacific region was found to bind France vis-à-vis all
States.
Article 103 UN Charter
Another facet of hierarchy in the international legal system is Art 103 UN
Charter. This provision is, amongst others, the key mechanism for
enforcing sanctions adopted by the Security Council under Art 41 UN
Charter. It sets forth that ‘in the event of a conflict between the obligations
of the Members of the United Nations under the present Charter and their
obligations under any other international agreement, their obligations under
the present Charter shall prevail’. Thus, when, for example, the Council
adopts a binding resolution ordering the imposition of sanctions against a
State, including the freezing of any assets, UN member States would not be
in breach of their international obligations under other bilateral or
multilateral agreements in implementing that resolution. This does not mean
that conflicting obligations are terminated; rather, they are simply
suspended for as long as the sanctions are in force. As a result, States
implementing their obligations under the UN Charter are not considered in
breach of other conflicting obligations (particularly non-performance)
contained in other treaties to which they are parties.
Article 103 has served as the legal basis for the implementation of
numerous sanctions regimes imposed by the UN since the 1990s.
Nonetheless, it was famously held by the ECJ that Art 103 cannot trump
jus cogens norms. In Yassin Abdullah Kadi and Al Barakaat International
Foundation v Council and Commission (2008), the ECJ ruled that the EC
Regulation embodying the sanctions against Al-Qaeda imposed by SC
Resolution 1267 was in breach of the right to be heard and the right to an
effective remedy. According to the ECJ, these rights constitute fundamental
principles of international law which not even the UNSC can ignore.
Looking for extra marks?
When there is a conflict between a jus cogens and a jus
dispositivum norm, the former should, in principle, prevail.
However, there have been cases before the European Court of
Human Rights (Al-Adsani v UK (2001)) and the ICJ
(Jurisdictional Immunities of the State, Germany v Italy:
Greece Intervening (2012)) in which this has not been obvious.
Both cases concerned the ostensible conflict between jus
cogens norms (eg war crimes or torture) and the principle of
State immunity. The latter was considered essentially of a
procedural character and hence in no direct conflict with the
substantive jus cogens rules. In the case now of a conflict
between two jus dispositivum norms, one may resort to classic
Latin maxims that are also applicable in the international
system: (a) lex specialis derogat legi generali, ie a special legal
regime has priority over a general law; and (b) lex posterior
derogat legi priori, namely, the more recent law overrides an
older law.
Revision tip
International law sets out obligations that may differ in nature
and legal consequences. The most significant difference is
between peremptory norms of international law (jus cogens)
that are not susceptible to derogation and other norms of
international law (jus dispositivum). Jus cogens norms
encompass fundamental principles of the international legal
order, such as the prohibition of aggression, torture, and
genocide. Such norms impose obligations erga omnes upon
States or international organizations, namely, obligations owed
to the international community as a whole. Erga omnes
obligations are not of a contractual nature.
Key cases
CASE FACTS PRINCIPLES
CASE FACTS PRINCIPLES
Accordance The Court was asked The Court construed the question
with to assess the legality narrowly and sought to address only
International of the unilateral whether there is a rule prohibiting such
Law of the declaration of a unilateral declaration under
Unilateral independence made customary law and not whether there
Declaration of by the was a rule permitting it. In analysing
Independence representatives of the relevant State practice, it concluded
in Respect of people of Kosovo on that ‘the practice of States in these
Kosovo, 17 February 2008. latter cases does not point to the
Advisory Absent a treaty, the emergence in international law of a
Opinion, ICJ Court had to assess new rule prohibiting the making of a
Rep (2010), p whether this declaration of independence in such
403 declaration was cases’ (para 79). This stance was
legitimate under criticized by Judge Simma in his
general international Declaration that is reminiscent of the
law and whether it Lotus principle. He held that: ‘The
was in breach of Court’s reading of the General
UNSC Resolution Assembly’s question and its
1244. reasoning, leaping as it does straight
from the lack of a prohibition to
permissibility, is a straightforward
application of the so-called Lotus
principle. By reverting to it, the Court
answers the question in a manner
redolent of nineteenth-century
positivism, with its excessively
deferential approach to State consent.
Under this approach, everything which
is not expressly prohibited carries with
it the same color of legality; it ignores
the possible degrees of non-
prohibition, ranging from “tolerated” to
“permissible” to “desirable”.’
Barcelona The case related to a The Court held that: ‘an essential
Traction, claim brought on distinction should be drawn between
CASE FACTS PRINCIPLES
Light and behalf of natural and the obligations of a State towards the
Power legal persons alleged international community as a whole,
Company Ltd, to be shareholders in and those arising vis-à-vis another
Judgment, a foreign limited State in the field of diplomatic
ICJ Rep liability company. It protection. By their very nature the
(1970), p 3 was claimed that former are the concern of all States. In
unlawful measures view of the importance of the rights
were taken against involved, all States can be held to
the company. This have a legal interest in their protection;
decision of the Court they are obligations erga omnes. Such
has principally been obligations derive, for example, in
cited because of an contemporary international law, from
obiter dictum on the outlawing of acts of aggression,
obligations erga and of genocide, as well as from the
omnes. The Court principles and rules concerning the
was under severe basic rights of the human person,
criticism during that including protection from slavery and
period for failing to racial discrimination …’ (paras 33–4).
uphold the
entitlement of
Ethiopia and Liberia
to invoke the
responsibility of
South Africa for the
apartheid regime in
Namibia in 1966. To
address this criticism,
the Court decided to
include a paragraph
in the decision
postulating the idea
of obligations owed
to the international
community as a
whole.
Key debates
Topic Formalism and the sources of international law
Author/academic J D’Aspremont
Viewpoint The theory of ascertainment which the book puts forward
attempts to dispel some of the illusions of formalism that
accompany the delimitation of customary international law. It
also sheds light on the tendency of scholars, theorists, and
advocates to deformalize the identification of international
legal rules with a view to expanding international law. The
book seeks to revitalize and refresh the formal identification
of rules by engaging with the postmodern critique of
formalism.
Source Formalism and the Sources of International Law: A Theory
of the Ascertainment of Legal Rules (Oxford: Oxford
University Press, 2011)
Topic Fragmentation
Author/academic B Simma
Viewpoint In his view, irrespective of whether we are in the presence of
an emerging system or an uncoordinated mess of diverse
mechanisms, the fact is that the present state of affairs,
characterized as an ‘explosion of international litigation and
arbitration’, has not led to any significant contradictory
jurisprudence of international courts; such cases remain the
exception and actually courts have gone to great lengths to
avoid contradicting each other.
