 Part 3 of the articles on the responsibility of states for internationally wrongful acts addresses the implementation of such responsibility and it is divided in two chapters. The first dealing with the invocation of the responsibility of a state and the second dealing with countermeasures as a way to implement such responsibility. Part 3 is probably the most conceptual part of the codification of state responsibility. It is also in that part that some of the most controversial issues are hidden when it comes to countermeasures. Well let us take the articles as they stand and address in turn as they do the invocation of the responsibility and later countermeasures. As you will see the two are intimately intertwined and linked. As far as the invocation of responsibility is concerned the suma di visio introduced by the articles is between what is called in article 42 the invocation of responsibility by an injured state and what is called in article 48 the invocation of responsibility by any state other than an injured state. Well this distinction intends to address a rather basic issue which state has the legitimate interest to trigger the rules on international responsibility. Under article 42 the injured state is defined as follows and let us read that provision carefully and please have it at hand it is in your reading material. I quote a state is entitled as an injured state to invoke the responsibility of another state if the obligation breached is out to a that state individually or b a group of state including that state or the international community as a whole and the breach of the obligation I specific especially affects that state or II is of such a character as radically to change the position of all the other states to which the obligation is owed with respect to the further performance of the obligation end of quote. Well this is a fairly conceptual definition which requires some explanation even if the underlying issue is fairly straightforward and it is to identify which state can lawfully claim to be the victim of the internationally wrongful act so as to officially require by all available legal means that the state responsible for the breach performs in its favor the new secondary obligations of cessation reparation and eventually assurances and guarantees of non-repetition in order to identify the injured or victim state the central issue is to determine to whom the obligation breached is owed article 42 distinguishes between three possible cases the first case is the easiest to understand it is when the obligation is owed to the injured state individually which means that the injured state has an individual right to the performance of the obligation breached and this is notably the case of obligations under bilateral treaty but this can also be the case under a multilateral treaty or a customary international law rule for instance the obligation under article 22 of the Vienna Convention on diplomatic relations to protect the diplomatic mission is an obligation that each receiving state owes individually to each foreign state having a mission on its territory and the same is true for instance for customary obligations relating to the immunity of states that will be studied later in the course likewise international obligations stemming from unilateral undertakings may be owed individually to states the second and third cases identified by article 42 is when the obligation breached is owed to I quote a group of states including that state or the international community as a whole the obligations that are here at stake can be owed to a group of states under a multilateral treaty or to the international community as a whole under a customary rule of international law the obligations here at stake are called collective obligations in the sense that the performance of those obligations is not owed to one state in particular but to a collectivity a group of state or the international community as a whole when the obligation is owed to the international community as a whole under a rule of customary international law the obligation is set to be erga omnes the concept of obligation erga omnes was introduced by the International Court of Justice in the Barcelona attraction case the court having famously drew what she called an essential distinction between obligations owed to particular states and those owed I quote towards the international community as a whole and this is the case of 1970 we shall come back to the notion of erga omnes obligations when speaking about states other than the interest state because as the court said in the Barcelona attraction case I quote all states can be held to have a legal interest in their protection because of the importance of the rights involved the collective interests examples of those obligations are human rights obligations or obligations to prevent the pollution of a specific environment like disease however the violation of those collective obligations only injures a particular state if some additional requirements are met article 42 b I refers to the case where the breach of the collective obligation which is does an obligation not individually owed to any specific state when that breach specially affects a particular state in such a case that specially affected state will be considered as the injured state the concept of being specially affected is taken from article 60 of the Vienna Convention on the law of the sea or on the law of treaties which relates to the exceptionality plenty contractors it means that the breach of the collective obligation must affect a state in a way which distinguishes it from the generality of the other states to which the obligation is owed and for instance if a state's party to the 1984 convention against torture again engages in torturing the national of another state the latter will be considered as specially affected and therefore injured or if an obligation to prevent the pollution of the sea is breached and the pollution reaches the shores of a specific state that state will be considered as specially affected and therefore injured under article 42 b I I the other possibility for being considered as an injured state when a collective obligation has been breached that other possibility is when the breach I quote again is of such a character as radically to change the position of all the other states to which the obligation is owed with respect to the further performance of the obligation end of quote by this article 42 refers to a specific category of collective obligations called interdependent obligations they are to be found in disarmament treaties nuclear free zone treaties are treaties establishing specific regimes like the 1959 Antarctic Treaty in those cases the performance of each party is effectively conditions conditioned upon the performance of each of the other parties and actually it requires such performance by others you may remember that those obligations are also mentioned under article 60 of the Vienna convention on the law of treaties and their breach may trigger the right to terminate to suspend or to withdraw from the treaty but states may be more interested in keeping the treaty and in having the legal relationship restored by claiming cessation of the breach and reparation and that is why article 42 considers that when such interdependent obligation is breached every other state to which the obligation is owed will per se be considered as affected and therefore injured