|Sovereignty is a core principle of international law. According to a widely accepted definition of the term in the 1928 Island of Palmas arbitral award,|
Multiple declarations by the UN, NATO, OSCE, the European Union, and individual States have confirmed that international law applies in cyberspace. Accordingly, so too does the principle of sovereignty. However, there is some debate as to whether this principle operates as a standalone rule of international law, the breach of which gives rise to state responsibility.
The remainder of this section proceeds on the basis of the former “sovereignty-as-rule” approach. Those espousing the latter “sovereignty-as-principle” approach should refer to other relevant sections of the legal analysis (such as that on the prohibition of intervention).
It is understood that sovereignty has both an internal and an external component. In the cyber context, the “internal” facet of sovereignty entails that “[a] State enjoys sovereign authority with regard to the cyber infrastructure, persons, and cyber activities located within its territory, subject to its international legal obligations.”
As a general rule, each State must respect the sovereignty of other States. It is clear that a cyber operation with severe destructive effects, comparable to a "non-cyber" armed attack or a use of force against a State, constitutes a violation of its sovereignty; however, with more subtle cyber operations, the question is far from settled.
The following modalities, highlighted in the Tallinn Manual 2.0, represent different ways of determining what a “sovereignty violation” might mean in the context of cyber operations:
Attributing the relevant cyber operation to a State different from the target State is a necessary prerequisite for qualifying the cyber operation as a violation of the target State's sovereignty.
Whether non-State actors can violate territorial sovereignty on their own is a matter of disagreement.
Notes and references
- Island of Palmas (Neth. v. U.S.), 2 RIAA 829, 838 (Perm. Ct. Arb. 1928).
- UNGA Res 71/237 (30 December 2015) UN Doc A/RES/20/237.
- North Atlantic Treaty Organization, 'Wales Summit Declaration' (issued by the Head of State and Government participating in the meeting of the North Atlantic Council in Wales (5 September 2015) para 72.
- Organization for Security and Cooperation in Europe, Decision No. 1202, OSCE Confidence-Building Measures to Reduce the Risks of Conflict Stemming from the Use of Information and Communication Technologies (Permanent Council, 10 March 2016) PC.DEC/1202.
- Council of the European Union,"Council Conclusions on the Joint Communication to the European Parliament and the Council: Resilience, Deterrence and Defence: Building strong cybersecurity for the EU" (Council conclusions, 20 November 2017),
- Michael N Schmitt, 'Virtual Disenfranchisement: Cyber Election Meddling in the Grey Zones of International Law' (2018) 19 ChiJIntlL 30,40; Tallinn Manual 2.0, commentary to rule 4, para 2 (‘States shoulder an obligation to respect the sovereignty of other States as a matter of international law’).
- See Michael N Schmitt and Liis Vihul, ‘Respect for Sovereignty in Cyberspace’ (2017) 95 Tex L Rev. 1639, 1649 (noting that States ‘voiced no meaningful objection to Rule 4’ and that ‘it appeared to be received knowledge that a primary rule on territorial-sovereignty violations existed and applied to cyber operations.’).
- Gary P. Corn and Robert Taylor, ‘Sovereignty in the Age of Cyber’ (2017) 111 AJIL Unbound 207, 208 (arguing that sovereignty is ‘a principle of international law that guides state interactions’).
- Jeremy Wright, ‘Cyber and International Law in the 21st Century’ (23 May 2018) (stating that he was ‘not persuaded that we can currently extrapolate from that general principle a specific rule or additional prohibition for cyber activity beyond that of a prohibited intervention. The UK Government’s position is therefore that there is no such rule as a matter of current international law’); see also Memorandum from JM O’Connor, General Counsel of the Department of Defense, ‘International Law Framework for Employing Cyber Capabilities in Military Operations’ (19 January 2017) (considering that sovereignty is not ‘a binding legal norm, proscribing cyber actions by one State that result in effects occurring on the infrastructure located in another State, or that are manifest in another State’), as cited by Sean Watts & Theodore Richard, 'Baseline Territorial Sovereignty and Cyberspace' (2018) 22 Lewis & Clark L. Rev. 771, 829.
- Cf. James Crawford, Brownlie's Principles of Public International Law (OUP 2012) 448
- Tallinn Manual 2.0, rule 2.
- Sovereignty over cyber infrastructure derives from the traditional concept of sovereignty, independent of the use of cyberspace. See Wolff Heintschel von Heinegg, 'Territorial Sovereignty and Neutrality in Cyberspace' (2013) 89 Int’l L. Stud. 123 (noting that '[t]erritorial sovereignty [..] implies that, subject to applicable customary or conventional rules of international law, the State alone is entitled to exercise jurisdiction, especially by subjecting objects and persons within its territory to domestic legislation and to enforce these rules.')
- UN GA Res 2625 (XXV) (24 October 1970) (Friendly Relations Declaration), preamble (emphasizing “that the purposes of the United Nations can be implemented only if States enjoy sovereign equality and comply fully with the requirements of this principle in their international relations”); Tallinn Manual 2.0, rule 4.
- Tallinn Manual 2.0, commentary to rule 4, para 5 and 12.
- See, eg, 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) (Judgment)  ICJ Rep 665, 704–05, paras 97–99 (holding that the presence of Nicaragua’s military personnel in the territory under Costa Rica’s sovereignty amounted to a violation of Costa Rica’s territorial sovereignty); see also Tallinn Manual 2.0, commentary to rule 4, para 6.
- Tallinn Manual 2.0, commentary to rule 4, para 7; commentary to rule 32, para 9.
- Tallinn Manual 2.0, commentary to rule 4, para 11.
- Tallinn Manual 2.0, commentary to rule 4, para 12.
- Tallinn Manual 2.0, commentary to rule 4, para 13.
- Tallinn Manual 2.0, commentary to rule 4, para 14.
- Tallinn Manual 2.0, commentary to rule 4, para 15.
- Tallinn Manual 2.0, commentary to rule 4, para 16.
- Tallinn Manual 2.0, commentary to rule 4, para 18.
- In favour: see, eg, Theodore Christakis, ‘The ICJ Advisory Opinion on Kosovo: Has International Law Something to Say about Secession?’ (2011) 24 LJIL 73, 84; Marcelo Kohen, ‘The Court’s Contribution to Determining the Content of Fundamental Principles of International Law’ in Giorgio Gaja and Jenny Grote Stoutenburg (eds), Enhancing the Rule of Law through the International Court of Justice (Brill 2012) 145. Against: see, eg, Tallinn Manual 2.0, commentary to rule 4, para 3.