- Responsibility of states — Vienna Convention on the Law of Treaties — Erga omnes obligations — Peremptory norms / ius cogens
This chapter demonstrates the necessary distinction between the two concepts in question, taking into consideration their different historical origins, their effects, and the reciprocal fields of application. It opposes the conception according to which only the rules creating obligations erga omnes could be considered as peremptory, as well as the theoretical opinion that all norms of jus cogens would produce, if breached, obligations erga omnes. It critically analyses how these erroneous conceptions are reflected in the solutions, although contradictory, adopted by the International Law Commission in the final draft on the responsibility of States approved in 2001. The last part of the chapter shows how the two concepts raise in their operation many different problems, which are not yet adequately considered in the legal scholarship.