 International law is a decentralized legal order. Every state is entitled to judge by itself if an internationally wrongful act has been committed. And eventually, to invoke either as an injured state or as a non-injured state the responsibility of another state for that breach. But as we have seen in the previous reading, there is a difference between invoking the responsibility of a state and being able to enforce that responsibility before an international court or an international tribunal. Absent state consent. There is no compulsory adjudication so that the injured state may be facing a situation where the responsible state will just flatly reject its claim. If that is the case, the rules on state responsibility and international law in general will risk being completely ineffective. Of course, the injured state may always press its claim and its demands present them again to the responsible state in the hope of finding an agreed settlement. The injured state may also put pressure on the responsible state by taking all sorts of unfriendly measures that are intrinsically legal, measures that are called retortions like postponing a state visit, limiting, suspending or even terminating the diplomatic ties between the two countries or preventing foreign officials to enter its territory or suspending a treaty in conformity with the law of treaties etc. But additionally, the injured state will also be entitled to press its claim against the responsible state by resorting to measures that are as such in breach of its international obligations, but for which the injured state will however not incur international responsibility because those measures, although illegal, are taken in response to a first violation. For instance, the injured state suspends the application of a trade treaty or the benefits of any other international obligation it owes to the responsible state like the benefit resulting from an air transport agreement. While such suspension cannot be justified under the treaty itself or the law of treaties in general, deliberately breaching the law in response to a first violation is not much different from taking justice in one's own hands. Measures of self-redress are usually forbidden in municipal law. By contrast, such enforcement measures are not prohibited in international law. And in fact, reciprocity, quid pro quo is at the heart of international law and reprisals have been traditionally tolerated in international law. And as we shall see in the last part of this course, armed reprisals are now, as a matter of principle, prohibited. But non-forcible reprisals are still very much part of international law today. And today, those non-forcible reprisals are called countermeasures. The second chapter of part three of the articles on the responsibility of states for internationally wrongful acts is about countermeasures. We have already come across the notion of countermeasures as a circumstance precluding wrongfulness under article 22 of Varsiois. But it is time now to make it more explicit and to try to understand what are countermeasures, when and why it is possible to resort to countermeasures who may resort to countermeasures and how countermeasures must be exercised. All those questions are dealt with under article 49 to 54 of the articles on states responsibility. Those articles reflect to a large extent customary international law, even if some of the procedural requirements set out in those articles probably still need to be confirmed by state practice. And because the ILC has codified countermeasures and that such codification represents acceptable international law, it is very likely that state practice will actually conform with them in the future. Let us first recall what is a countermeasure. It is an internationally wrongful act taken in response to a previous internationally wrongful act. As stated earlier, countermeasures are intrinsically illegal and are therefore distinct from retortion measures which are unfriendly but intrinsically legal and therefore unregulated by international law. Because the countermeasure is the second breach in response of a previous breach, its wrongfulness will be precluded. The author of the countermeasure must be the injured state within the meaning of article 42. And the target of such countermeasure must be the responsible state and the responsible state only. And this is of course common sense and it has been recalled by the ICJ in the Capsicowo Naguimaro's case. And I quote, in the first place a countermeasure must be taken in response to a previous international wrongful act of another state and must be directed against that state. And of quote. Furthermore, as recalled by article 49 paragraph 1, countermeasures must only be taken, I quote, in order to induce the responsible state to comply with its obligations under part two of the articles. That is, its new substantive obligations of cessation, reparation and if the circumstances so require assurances and guarantees of non-repetition. In other words, countermeasures are enforcement measures, measures whose only purpose is to obtain from the responsible state that it complies with the new obligations that were triggered as a result of its wrongful act. Countermeasures are not punitive measures, they are law enforcement measures typical of a decentralized legal order. And this explains that countermeasures are, by nature, temporary. They must be terminated as soon as the responsible state has complied with its secondary obligations. And this is made clear by article 53. Because of their temporary nature, countermeasures are, according to paragraph 2 and 3 of article 49, I quote, limited to the non-performance for the time being of international obligations of the state taking the measure, the measures towards the responsible state. And I quote again, they shall, as far as possible, be taken in such a way as to permit the resumption of performance of the obligations in questions. And I quote. Well, this being said, some obligations may not be temporarily suspended by the injured state by means of countermeasures. Those obligations may not be affected by countermeasures. And the injured state is required to continue to respect these obligations in its relations with the responsible state. Those obligations are listed under article 50 and will turn to them just after this video. Let me end this video by recalling the two customary principles limiting the exercise of countermeasures. Countermeasures can only be resorted to if they are necessary to protect the rights of the injured state. And they must be resulted to in a proportionate way. Let us turn also to those requirements in the next reading.