Why in News?

• The US has threatened to target few historical sites if Iran retaliates to attack US in revenge. This is a breach of JUS COGENS as targeting cultural sites amounts to a war crime.

Jus Cogens:

• JUS COGENS or ius cogens, meaning “compelling law” in Latin, are rules in international law that are peremptory or authoritative, and from which states cannot deviate.
• The jus cogens rules have been sanctioned by the Vienna Conventions on the Law of Treaties of 1969 and 1986. According to both Conventions, a treaty is void if it breaches jus cogens rules.
• Article 64 of the 1986 Convention, “Emergence of a new peremptory norm of general international law (jus cogens)”, says: “If a new peremptory norm of general international law emerges, any existing treaty which is in conflict with that norm becomes void and terminates.”
• So far, an exhaustive list of jus cogens rules does not exist. However, the prohibition of slavery, genocide, racial discrimination, torture, and the right to self-determination are recognised norms.
• The prohibition against apartheid is also recognised as a jus cogens rule, from which no derogation is allowed, since apartheid is against the basic principles of the United Nations.

Vienna Convention on Law of Treaties:

• Article 53 of the 1969 Convention says: “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 this no derogation is permitted and which can be modified only by a subsequent norm of general international law having the same character.
• Article 64 says- If a new peremptory norm of general international law emerges, any existing treaty which is in conflict with that norm becomes void and terminates.
• Besides treaties, unilateral declarations also have to abide by these norms.