conditions, the procedural requirements do not have to be met when compliance with them would defeat the purpose of the intended countermeasures.25 15. In Costa Rica’s view, countermeasures may be taken by the injured State, i.e., the State specifically affected by the breach, as well as third States in response to violations of obligations of an erga omnes nature or upon request by the injured State.26 Thus, States may respond collectively to cyber or non-cyber operations that amount to internationally wrongful acts, by resorting to cyber or non-cyber countermeasures. Countermeasures must be distinguished from acts of retorsion, i.e., unfriendly acts taken in response to lawful but equally unfriendly acts by another State, such as the suspension of diplomatic relations.27 Measures of retorsion are also available in cyberspace, including in response to wrongful or unfriendly cyber operations. 16. Other circumstances precluding wrongfulness under customary international law which are also applicable in the context of cyber operations are consent, necessity, force majeure, and self-defense, addressed below. Peaceful settlement of disputes 17. In accordance with Article 2(3) of the UN Charter, States ‘shall settle their international disputes by peaceful means in such a manner that international peace and security, and justice, are not endangered’. Likewise, under Article 33(1) of the Charter, in the case of a dispute ‘the continuance of which is likely to endanger the maintenance of international peace and security’, States ‘shall, first of all, seek a solution by negotiation, enquiry, mediation, conciliation, arbitration, judicial settlement, resort to regional agencies or arrangements, or other peaceful means of their own choice.’ They must do so in good faith.28 Both provisions encapsulate the customary principle of peaceful settlement of disputes,29 which applies to factual or legal disputes involving cyber operations.30 Sovereignty 18. Sovereignty is a fundamental principle of international law, underpinning the entire international legal order and firmly grounding the position of States therein. Sovereignty has been traditionally understood in a territorial and physical sense. It means, first and foremost, a State’s right to exercise legislative, adjudicative, and enforcement jurisdiction in its territory, ILC, ‘Fourth report on State responsibility, by Mr. Gaetano Arangio-Ruiz, Special Rapporteur’, A/CN.4/444 and Add.1-3, 1992, para. 16. 26 Articles 48 and 54, ILC Articles (n 8). 27 Draft ILC Articles (n Error! Bookmark not defined.), Commentary to Chapter II, para. 3. 28 Tallinn Manual 2.0 (n 4), Rule 65, esp. para. 14, at 308. 29 UN General Assembly (UNGA), ‘Declaration on Principles of International Law concerning Friendly Relations and Cooperation among States in accordance with the Charter of the United Nations’, A/RES/2625(XXV), 1970 (‘Friendly Relations Declaration’), Preamble, lit ‘b’ and Principle II. 30 Tallinn Manual 2.0 (n 4), Rule 65. 25 5