New Technologies in International Law / Tymofeyeva, Crhák et al.

1. The no-harm- due diligence duo: A rule(s) for all seasons? The obligation to prevent transboundary harm (alternatively the no-harm principle) has been formulated in the Trail Smelter Arbitration 66 and was considered customary international law by the International Court of Justice (ICJ) in the Corfu Channel case 67 , a conclusion which has been reaffirmed in the Pulp Mills and the Certain Activities in the Border Area cases. 68 According to said principle, States have an obligation to prevent the use of their territory for activities causing injury or damage in the territory of another State as well as a duty to prevent transboundary harm from hazardous activities. It is considered a core part of international environmental law and of its many regimes (e.g. the law of international watercourses) 69 and has been developed extensively within this context. Due diligence is a very old concept in international law referred to in very old and very recent arbitral awards, 70 and in decisions of international tribunals, namely the ICJ 71 and the International Tribunal on the Law of the Sea (ITLOS) 72 and has been accepted as a general principle of law. 73 There are many scholarly debates as to the nature and even the definition of due diligence as it has been called a “duty”, “obligation” “principle” and “rule”, thus creating wide doctrinal confusion. 74 Developing a commonly accepted definition of due diligence is beyond the scope of this paper. Nevertheless, for working reasons I will adopt that due diligence works through introducing positive obligations upon states to prevent unlawful situations and it can function both as a primary and a secondary international law rule. In the context of this paper, I submit that the no-harm principle, and the due diligence obligations it creates, can be applied to cyberspace. This application would 66 Trail Smelter Case (United States of America v. Canada) Judgment (1938, 1941) 3 RIAA 1905 ICJ Rep 29. 67 ICJ, Corfu Channel (United Kingdom of Great Britain and Northern Ireland v Albania) Judgment [1949] ICJ Rep 4. 68 ICJ Pulp Mills on the River Uruguay (Argentina v Uruguay) Judgment [2010] ICJ Rep 2010, p. 14; ICJ, Certain Activities Carried Out by Nicaragua in the Border Area (Costa Rica v. Nicaragua) and Construction of a Road in Costa Rica along the San Juan River (Nicaragua v. Costa Rica) Merits, Judgment [2015] ICJ Rep 2015. 69 Susane Schmeier and Joyeeta Gupta, ‘The principle of no significant harm in international water law’ (2020) 20 International Environmental Agreements: Politics, Law and Economics 597. 70 Youmans (U.S.) v. United Mexican States, 4 R.I.A.A. 110, 116 (Gen. Cl. Comm’n 1926) ; Permanent Court of Arbitration, PCA, South China Sea Arbitration, Philippines v. China, Award of 12 July 2016, PCA Case No 2013-19, ICGJ 495, para 744. 71 Corfu Channel Case (n 13) p. 22; ICJ Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v. Serbia and Montenegro) , Judgment [2007] ICJ Rep 43; Pulp Mills Case (n 68), paras 101, 197 and 204. 72 ITLOS Seabed Disputes Chamber, Responsibilities and Obligations of States Sponsoring Persons and Entities with Respect to Activities in the Area , Advisory Opinion [2011] ITLOS Reports 2011, paras 110–112, 117–120, 131–132; ITLOS, Request for an Advisory Opinion Submitted by the Sub-Regional Fisheries Commission ( SRFC ), Advisory Opinion [2015] ITLOS Reports 2015, paras 125–132, 146–150. 73 Joanna Kulesza, Due Diligence in International Law (Brill 2016), p. 19. 74 Peters A, Krieger H and Kreuzer L ‘Due Diligence in the International Legal Order Dissecting the Leitmotif of Current Accountability Debates’ Peters A, Krieger H, Kreuzer L (eds), Due Diligence in the International Legal Order (OUP, 2020); Brunnée J, ‘Procedure and Substance in International Environmental Law’ (2020) 405 Hague Academy Collected Courses 70.

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