The concept of obligations erga omnes and the rules governing the enforcement of international law do not exist in a legal vacuum. Their analysis, in the following chapters, depends on a number of basic concepts and notions. The purpose of this chapter is to introduce and clarify these concepts and notions. Three aspects in particular are to be considered: Section 1.1 briefly summarises legal rules governing countermeasures and ICJ proceedings as the two means of law enforcement relevant to the present study. Section 1.2 introduces the concept of standing to react against internationally wrongful acts, whose interpretation occupies much of the subsequent analysis. Finally, section 1.3 addresses the distinction between individual and general legal interests, which is at the heart of modern discussions about standing.

Countermeasures and ICJ proceedings

As a first step, it is necessary to introduce the two forms of responses addressed in the following: countermeasures and ICJ proceedings. At the outset, it is worth reiterating that although focusing on the two forms of responses, this study is not about the law of countermeasures or ICJ claims as such. It is assumed that if indeed, all States should be entitled to respond against erga omnes breaches, their responses would have to conform with the normal requirements governing ICJ claims and countermeasures. Subsequent chapters will therefore not address these other requirements, but take them for granted.