Jus Cogens are the highest source of international law to which all states must abide regardless of their consent to that norm or not

Published: 2019/12/04 Number of words: 1073

Certain obligations are erga omnes jus cogens. Erga Omnes can be said to be the obligation while jus cogen is the norm which the state must be obliged to follow. These are a source of international law which are of a different nature than other sources of international law, whether they are derived from custom or treaty. (Shaw:2009). They are unlike ordinary customary law and treaties which normally require consent from states. These norms are legally binding and cannot be violated by any state regardless of whether they consent to the norm or not.

Erga Omnes were recognised in the Barcelona Traction Case as being obligations of a State toward the International Community as a whole. Examples of erga omnes include the duty to outlaw serious human rights violations such as aggression and genocide (highlighted in the Nicaragua Case). It also includes the obligation to prohibit torture as illustrated in the Furundzija Case.

Rules of jus cogens are substantive rules which are recognised in law as having obtained a higher status. Criddle et al postulates that the term jus cogens refers to a norm which commands peremptory authority and which supersedes conflicting treaties and custom. A jus cogen is a peremptory norm which is recognised at law as one ‘accepted and recognised 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’ (Vienna Convention on the Law of Treaties 1969).

The International Law Commission has put forward some examples of crimes which they consider jus cogen. These crimes are those of a particularly heinous nature and includes the unlawful use of force, genocide, slave trading and piracy (Yearbook of the ILC, 1996).

The higher status of jus cogens was further identified in US v Matta-Ballesteros when it was said ‘jus cogens norms are ‘nonderogable and peremptory, enjoy the highest status within customary international law, are binding on all nations, and cannot be pre-empted by treaty’. It can therefore be said that certain norms which rise to the status of jus cogens constitute obligatio erga omnes and are inderogable (Bassiouni:1996).

J.Sktucki:1974 suggests that the concept of jus cogens is one based on the notion of fundamental and superior values. It is suggested therefore that if there is a hierarchy of international law (legal scholarly opinion widely argues to the contrary) jus cogens sits at the top. This means certain fundamental norms are given quasi-constitutional status (Koskenniemi:1997).

As these norms are binding, have peremptory force and cannot be derogated from except by another peremptory rule, it is suggested they must be followed regardless of the consent of states. The provisions of the Vienna Convention lends weight to this suggestion. Article 53 states that any treaty which is in conflict with a jus cogens is void ab initio. Article 41(2) of the ILC’s Articles on State Responsibility 2001 provides that no states shall recognise as lawful a ‘serious breach’ of a peremptory norm. Furthermore any reservations to treaties which offend a jus cogen will likely be unlawful. In Caseese:2005 it was suggested that states which violate jus cogen rules may not attract claims of state immunity. These norms are not only non-derogable in times of peace but also of war, further illustrating they are of the highest status.

The result is that certain norms must be followed by all states and when they are not, other states may exercise universal jurisdiction to ensure the continuance of that norm. This was illustrated by the International Criminal Tribunal for the Former Yugoslavia where the tribunal said in Prosecutor v Furundzija that prohibition against torture was a jus cogen norm and therefore every state is entitled ‘to investigate, prosecute and punish or extradite individuals accused of torture, who are present in a territory under its jurisdiction’. Janis et el:2006 says the rationale behind this is that those who breach these norms become hostis humani generis which means an enemy against all mankind.

In conclusion, there are a number of rules which are awarded the highest status which can be attained by any norm. These are fundamental rules which are accepted by the international community and no exceptions to these rules are permitted, whether states consent to them or not. These crimes, which are categorised as jus cogens rules, give rise to erga omnes obligations and affect the international community in its entirety. States may exercise universal jurisdiction and in fact have an obligation to do so against the perpetrators of these crimes.


Evan.J.Criddle & Evan Fox-Decent, A Fiduciary Theory of Jus Cogens, The Yale Journal of International Law, Vol.34:331
J.Sztucki, Jus Cogens and the Vienna Convention on the Law of Treaties, New York, 1974
Martti Koskenniemi, Hierarchy in International Law: A Sketch, 8 EUR. J. INT’L. L. 566, 566 (1997)
M.Cherif Bassiouni, International Crimes: Jus Cogens and Obligatio Erga Omnes, Law and Contemporary Problems, Vol.59:No.4
M. Cherif Bassiouni, States of Emergency and States of Exception: Human Rights
Abuses and Impunity under Color of Law, 125

Cassese, International Law, 2nd Ed, Oxford University Press, 2005
Janis M & Noyes J, International Law, Cases and Commentary, 3rd Ed, Thompson West, 2006
M.Shaw, International Law, 6th Ed, Cambridge University Press, 2009

Yearbook of the ILC, 1996, Vol II

ILC’s Articles on State Responsibility 2001
Vienna Convention on the Law of Treaties 1969

Barcelona Traction Case, 1970, ICJ
Prosecutor v Furundzija, 2002, ICJ
The Republic of Nicaragua v United States of America 1984, ICJ
US v Matta-Ballesteros 700 F.Supp.528 (1988)

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