sovereignty or other rules of international law.40 As such, Costa Rica believes that, in some circumstances, cyber espionage may amount to a breach of State sovereignty. Non-intervention 23. The principle of non-intervention is grounded in customary international law and prohibits States from interfering directly or indirectly with matters within the domestic jurisdiction of other States, i.e., their internal or external affairs.41 According to the ICJ, a prohibited intervention is one bearing ‘on matters in which each State is permitted, by the principle of State sovereignty, to decide freely’.42 Examples include ‘the choice of a political, economic, social and cultural system, and the formulation of foreign policy’,43 whether these are carried out by private or public entities,44 and irrespective of a State’s new undertakings under international law. Moreover, according to the ICJ, a wrongful intervention is one which ‘uses methods of coercion in regard to such choices, which must remain free ones’.45 24. Coercion is clear-cut when a State uses or threatens to use force against another one.46 Nonetheless, it can also occur in a multitude of ways where one State, directly or indirectly through support for non-State actors, deprives another State of the capacity to make free and informed choices pertaining to its internal or external affairs.47 Coercion may occur when a State provides financial or other forms of support to secessionist, subversive or violent groups in the territory of another State, when it exercises significant political or economic pressure on another State, or when it engages in or supports subversive or hostile propaganda or the dissemination of false news that interfere in the internal or external affairs of another State.48 Moreover, coercion needs not be successful in intervening within a State’s internal or external affairs. Mere threats of intervention or acts seeking to interfere within another State’s domaine reservé may also breach the principle.49 For such breaches to occur, it suffices that a State intends to coerce another State, employs coercive methods, or eventually causes coercive effects in another State. 25. In Costa Rica’s view, these various forms of coercion may well be carried out in or through ICTs and amount to violations of the principle of non-intervention insofar as they interfere with a State’s internal or external affairs.50 A prominent example of a breach of non-intervention are ransomware attacks crippling or simply interfering with a State’s ability ‘The Oxford Process on International Law Protections in Cyberspace: A Compendium’, Oxford Institute for Ethics, Law and Armed Conflict (ELAC), October 2022, at 280, para. 3. 41 Friendly Relations Declaration (n 29), Preamble, lit c, and Principle III. 42 Nicaragua case (n 11), para. 205 43 Ibid. 44 Tallinn Manual 2.0 (n 4), Rule 66, especially paras 8-11, at 315-316. 45 Nicaragua case (n 11), para. 205. 46 Ibid. 47 Tallinn Manual 2.0 (n 4), Rule 66, paras 18, 23, at 317, 319-320. 48 UNGA ‘Declaration on the Inadmissibility of Intervention and Interference in the Internal Affairs of States’ UN Doc A/RES/36/103 (1981), II. 49 Ibid. 50 Tallinn Manual 2.0 (n 4), Rule 66. 40 7