Jus cogens, or compelling law, refers to a category of norms that govern customary international law. The Latin term is used interchangeably with the English term “peremptory norm”.
Jus cogens norms differ from other norms in two key respects.
- First, as the translation suggests, jus cogens norms are mandatory.
- They compel lawmakers to act in a specific manner. If a provision of a treaty conflicts with an existing jus cogens norm, that provision is invalid insofar as it violates jus cogens.
- Second, for a norm to be considered a jus cogens norm, its mandatory effect must be universally accepted by the international community.
- In practice, this limits jus cogens norms to prohibitions against egregious conduct, such as crimes against humanity, genocide, slavery and human trafficking.
While there have been attempts to classify certain rules, rights, and duties as peremptory norms, these have not been very successful.
[Last updated in June of 2023 by the Wex Definitions Team]