Jus cogens norms have been called the superheroes of international law because they are both extremely powerful and completely fictional. Is this characterization accurate?
“Jus cogen” norms are rules of customary international law that have become so familiar in the system that they are treated as the inviolable rights under the international law. It has to be noted that customary international law is created through custom and this indicates that the acceptance of persistent unlawful acts by other states over a period of time creates a new legal principle under international law. In ordinary circumstances, a treaty obligation will prevail over customary international law unless that specific law has gained the status of a “jus cogen” norm.
Hence, the States considers the “Jus cogens” norms as inviolable. This essentially means that any international instrument will not apply if its effect would be to violate a “jus cogens” norm. And neither will contrary State practice give rise to a new custom of international law.
These norms are extremely powerful as these norms were created when State practice by a significant majority of States along with the relevant opinio juris existed for a sufficiently long time. Thereafter, the customs becomes a norm of “jus cogens” and enters into a distinct category under international law. Some prominent examples of “jus cogens” norms include the prohibitions on slavery, torture and piracy. In essence, this means that under no circumstances international practice could bring back slavery as a custom of international law in violation of this norm. Also, neither could the same be done through a treaty because it would be invalid.
Moreover, it is true that these norms are not easy to identify. However, that is not the same thing as saying that they do not exist. The essence of international law lies on the consent of its subjects, the States. “Jus cogens” norms exist because not only do the practices of most States comply with them, the opinio juris of those States except their status as higher than that of customary international law. In order to argue that a “jus cogens” norm is fiction because it does not exist is to argue that law does not exist because it cannot be seen. “Jus cogens” norms, like law, exist because the States to which they apply accept them. In circumstances, where a practice reaches the extent of compliance necessary, a “jus cogens” norm begins to develop in that area. These areas typically govern topics regarding which States hold strong opinion, much like their citizens. Torture, slavery and genocide for instance are norms because the overwhelming majority of States, just like the overwhelming majority of people, find these to be not only repulsive but also criminal and inhumane. And it is this shared belief that provides the force that a “jus cogens” norm wields. In conclusion, “jus cogens” norm exist because the feeling exists among States that some things ought never to be done.å