|[[File:Crown-Silhouette.svg|left|frameless|200x200px]][[Sovereignty]] is a core principle of international law. According to a widely accepted definition in the ''Island of Palmas'' arbitral award of 1928,<blockquote>[s]overeignty in the relations between States signifies independence. Independence in regard to a portion of the globe is the right to exercise therein, to the exclusion of any other State, the functions of a State.<ref>''Island of Palmas (Neth. v. U.S.)'', 2 RIAA 829, 838 (Perm. Ct. Arb. 1928).</ref></blockquote>According to multiple declarations by the UN,<ref>United Nations General Assembly, [http://www.un.org/ga/search/view_doc.asp?symbol=A/70/174&referer=/english/&Lang=E ''Report of the Group of Governmental Experts on Developments in the Field of Information and Telecommunications in the Context of International Security''], A/70/174 (22 July 2015).</ref> NATO,<ref>[https://www.nato.int/cps/ic/natohq/official_texts_112964.htm ''Wales Summit Declaration, Issued by the Heads of State and Government participating in the meeting of the North Atlantic Council in Wales''] (5 September 2015) para. 72.</ref> OSCE,<ref>Organization for Security and Co-operation in Europe, Permanent Council, [https://www.osce.org/pc/227281?download=true ''Decision No. 1202, OSCE Confidence-Building Measures to Reduce the Risks of Conflict Stemming from the Use of Information and Communication Technologies''], PC.DEC/1202 (10 March 2016).</ref> and individual States, international law applies in cyberspace, and hence also the principle of sovereignty applies in cyberspace. It is the subject of some debate to what extent this principle operates as a standalone rule of international law.
* For the proponents of this view, the prohibition on violation of sovereignty is a substantive primary rule of international law. This view is at the basis of the analysis in the Tallinn Manual<ref>Michael N Schmitt, 'Virtual Disenfranchisement: Cyber Election Meddling in the Grey Zones of International Law' (2018) 19 Chi. J. Int'l L. 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’).</ref> and it has reportedly not been challenged by any of over fifty States that had participated in the process of consultations of the Manual in 2017.<ref>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.’).</ref>
* By contrast, the opposing view considers that sovereignty is "a principle of international law that guides state interactions, but is not itself a binding rule".<ref>GP Corn and R Taylor, ‘Sovereignty in the Age of Cyber’ (2017) 111 AJIL Unbound 207, 208.</ref> It was originally formulated by two high-level US government legal advisors writing in their private capacity<ref>Gary Corn was the Staff Judge Advocate at the US Cyber Command and Robert Taylor was Former Principal Deputy General Counsel at the US Department of Defense. See Corn and Taylor
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 the [[prohibition of intervention]].