State responsibility conduct, and consent in relation to the underlying obligation itself. In the case of a bilateral treaty, the States parties can at any time agree to terminate or suspend the treaty, in which case obligations arising from the treaty will be terminated or suspended accordingly.320 But quite apart from that possibility, States have the right to dispense with the performance of an obligation owed to them individually, or generally to permit conduct to occur which (absent such permission) would be unlawful so far as they are concerned. In such cases, the primary obligation continues to govern the relations between the two States, but it is displaced on the particular occasion or for the purposes of the particular conduct by reason of the consent given. (3) Consent to the commission of otherwise wrongful conduct may be given by a State in advance or even at the time it is occurring. By contrast, cases of consent given after the conduct has occurred are a form of waiver or acquiescence, leading to loss of the right to invoke responsibility. This is dealt with in article 45. (4) In order to preclude wrongfulness, consent dispensing with the performance of an obligation in a particular case must be “valid”. Whether consent has been validly given is a matter addressed by international law rules outside the framework of State responsibility. Issues include whether the agent or person who gave the consent was authorized to do so on behalf of the State (and if not, whether the lack of that authority was known or ought to have been known to the acting State), or whether the consent was vitiated by coercion or some other factor.321 Indeed there may be a question whether the State could validly consent at all. The reference to a “valid consent” in article 20 highlights the need to consider these issues in certain cases. (5) Whether a particular person or entity had the authority to grant consent in a given case is a separate question from whether the conduct of that person or entity was attributable to the State for the purposes of chapter II. For example, the issue has arisen whether consent expressed by a regional authority could legitimize the sending of foreign troops into the territory of a State, or whether such consent could only be given by the central Government, and such questions are not resolved by saying that the acts of the regional authority are attributable to the State under article 4.322 In other cases, the “legitimacy” of the Government which has given the consent has been questioned. Sometimes the validity of consent has been questioned because the consent was expressed in violation of relevant provisions of the State’s internal law. These questions depend on the rules of international law relating to the 320 1969 Vienna Convention, art. 54 (b). See, e.g., the issue of Austrian consent to the Anschluss of 1938, dealt with by the Nuremberg Tribunal. The tribunal denied that Austrian consent had been given; even if it had, it would have been coerced and did not excuse the annexation. See “International Military Tribunal (Nuremberg), judgment and sentences October 1, 1946: judgment”, reprinted in AJIL, vol. 41, No. 1 (January 1947) p. 172, at pp. 192–194. 322 This issue arose with respect to the dispatch of Belgian troops to the Republic of the Congo in 1960. See Official Records of the Security Council, Fifteenth Year, 873rd meeting, 13–14 July 1960, particularly the statement of the representative of Belgium, paras. 186– 188 and 209. 321 73 expression of the will of the State, as well as rules of internal law to which, in certain cases, international law refers. (6) Who has authority to consent to a departure from a particular rule may depend on the rule. It is one thing to consent to a search of embassy premises, another to the establishment of a military base on the territory of a State. Different officials or agencies may have authority in different contexts, in accordance with the arrangements made by each State and general principles of actual and ostensible authority. But in any case, certain modalities need to be observed for consent to be considered valid. Consent must be freely given and clearly established. It must be actually expressed by the State rather than merely presumed on the basis that the State would have consented if it had been asked. Consent may be vitiated by error, fraud, corruption or coercion. In this respect, the principles concerning the validity of consent to treaties provide relevant guidance. (7) Apart from drawing attention to prerequisites to a valid consent, including issues of the authority to consent, the requirement for consent to be valid serves a further function. It points to the existence of cases in which consent may not be validly given at all. This question is discussed in relation to article 26 (compliance with peremptory norms), which applies to chapter V as a whole.323 (8) Examples of consent given by a State which has the effect of rendering certain conduct lawful include commissions of inquiry sitting on the territory of another State, the exercise of jurisdiction over visiting forces, humanitarian relief and rescue operations and the arrest or detention of persons on foreign territory. In the Savarkar case, the arbitral tribunal considered that the arrest of Savarkar was not a violation of French sovereignty as France had implicitly consented to the arrest through the conduct of its gendarme, who aided the British authorities in the arrest.324 In considering the application of article 20 to such cases it may be necessary to have regard to the relevant primary rule. For example, only the head of a diplomatic mission can consent to the receiving State’s entering the premises of the mission.325 (9) Article 20 is concerned with the relations between the two States in question. In circumstances where the consent of a number of States is required, the consent of one State will not preclude wrongfulness in relation to another.326 Furthermore, where consent is relied on to 323 See paragraph (6) of the commentary to article 26. UNRIAA, vol. XI (Sales No. 61.V.4), p. 243, at pp. 252–255 (1911). 325 Vienna Convention on Diplomatic Relations, art. 22, para. 1. 326 Austrian consent to the proposed customs union of 1931 would not have precluded its wrongfulness in regard of the obligation to respect Austrian independence owed by Germany to all the parties to the Treaty of Peace between the Allied and Associated Powers and Germany (Treaty of Versailles). Likewise, Germany’s consent would not have precluded the wrongfulness of the customs union in respect of the obligation of the maintenance of its complete independence imposed on Austria by the Treaty of Peace between the Allied and Associated Powers and Austria (Peace Treaty of Saint-Germain-enLaye). See Customs Régime between Germany and Austria, Advisory Opinion, 1931, P.C.I.J., Series A/B, No. 41, p. 37, at pp. 46 and 49. 324