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Review 2018-2019 - Volume 57

Espionage and International Law in the Age of Permanent Competition
Legal Advisor, Researcher, Member of the Italian Group and the International Society for Military Law and the Law of War

Table of Contents
  1. Introduction
  2. The Age of Permanent Competition According to the New US National Security Strategy
  3. A Modern Definition of Espionage
  4. May Espionage Outside an Armed Conflict be Held Legal Under International Law?
    1. Espionage is Legal Due to the End of the War/Peace Dualism
    2. The Legality of Espionage is the Same in Both Peace and War
    3. Espionage is Legal Under Customary Law
  5. Balancing Espionage With its Consequences
    1. The Right Proportionality Test
    2. The Right to Privacy
    3. The Principle of Sovereignty
    4. The Prohibition of Intervention in Internal Affairs
    5. The Immunity of Diplomatic Missions
  6. Conclusion

I. Introduction

Joseph Palmi [Joe Pesci]: You're the guys that scare me. You're the people that make big wars.
Edward Wilson
[Matt Damon]: No, we make sure the wars are small ones, Mr Palmi.

1 Competition is a recurring theme in the international legal scholarship. 2 Derived from neoclassical economic theories, since the fall of Communism the principle of ‘inherent’ competition has spilled over into other areas of social sciences, greatly influencing the academic and political discourse. In neoclassical economic models, a necessary precondition for the exercise of competition is the presence of a strong and clear regulatory framework, to be enforced or supervised by a centralised authority (the State, a supranational authority, an independent agency, etc.). In this context, the economic system is conceived to head towards perfect competition, that

* Email: This article is written in the author’s personal capacity. The views and opinions expressed are exclusively his own. Information and data contained in this article have been gathered from open sources only. The author wishes to thank Dr Tommaso Natoli (University of Roma Tre) for his support in the initial stages of the author’s research. Back
1 Quotes taken from the movie ‘The Good Shepherd’ (Universal Pictures 2006), directed by Robert De Niro. In the movie, Matt Damon, aka Edward Wilson Sr, plays the role of a prominent CIA officer, who is profoundly involved in the Agency’s foundation and development. His character strongly resembles the famous James Jesus Angleton, Chief of CIA Counterintelligence from 1954 to 1975. Back
2 See on the matter the outstanding E. Benvenisti & G.W. Downs, ‘The Empire’s New Clothes: Political Economy and the Fragmentation of International Law’, Vol. 60 Stanford Law Review 2007, pp. 595-631. Back


is, roughly, a situation in which nobody makes profits anymore. Perfect competition is in turn based on perfect knowledge, which is supposed to be freely available to all market participants. In the short term, competition generates winners and losers, but in the long term, a competitive model should represent the optimal economic situation for all market participants. 3

However, what happens if some market participants develop the knowledge which is necessary for other participants to be able to compete, retain it for themselves and eventually protect it, in the absence of a centralised authority who may oblige them to release the information in their possession? Should the second group of market participants coerce the first to obtain such knowledge? Are there instruments other than force – rectius, more cost-effective than force – to reach the same result? For instance, should market participants try to secretly circumvent the protective means set up by their competitors to obtain the information in question? In other words, should they spy on their fellow market participants to achieve perfect competition and wealth? If one transferred this scenario into the reality of international relations and substituted market participants with States, the latter question would turn into: ‘Should States spy on each other to achieve peace and prosperity’?

There is a logical nexus between espionage and competition among States, since the higher the level of interest on specific information, the higher the competition among States guaranteeing access to it. In a volatile global scenario, where the quest for power is taking a new and unprecedented shape, the issue of the legality of means and methods ‘other than war’, like espionage, used by States in their increasingly tougher mutual relations, is becoming pressing. More generally, rerouting the politics of international law towards the acceptance of more ‘resilient’ law principles and institutions may help the international order to survive this period of great uncertainty. 4 This may include breaking legal taboos, and admitting the legality of certain measures and practices, like espionage, that are central to the dynamics of international politics, but that have so far been looked at with discredit by the international legal community. The risk of inaction is simply that of making international law irrelevant to the development of international relations. However, as legal scholars know well, the withdrawal of law from the international arena comes with a price. As Professor Franck wrote in 2006 on the occasion of the centennial of the American Journal of International Law, ‘[w]hen a community loses faith in law’s power to restrain and channel conduct, this perception propels the descent into anarchy’. 5

In this framework, this article examines the potential legality of espionage under international law in light of the current neo-realist twist in international relations. The starting basis of our study is the new national security strategy adopted by the most powerful actor in the international arena, namely the US, which is assessed in Section II. This serves the purpose of highlighting that the US foreign policy is heading towards harder and harder forms of competition with other States, denoting the decline of the peace/war dualism and the rise of a ‘grey area’ in international relations (a phenomenon that we call ‘the age of permanent competition’).

The idea that States are increasingly interpreting the nature of the world order through neo-realist lens is presented as an assumption and this could perhaps be misunderstood as an oversimplification. Nations other than the US may definitely have different views with regard to the nature and limits characterizing the use of State powers within the international system. Many States – especially small and medium powers – could persist in adopting a more liberal or

3 These brief introductory notes only serve to present the concept of competition in an elementary manner and are by no means intended to provide a comprehensive or specific economic analysis. A detailed study of all the theses on neoclassical economics may be found in Y.M. Madra, Late Neoclassical Economics: The Restoration of Theoretical Humanism in Contemporary Economic Theory (Abingdon & New York, Routledge, 2017), p. 91. Back
4 See on the matter A. Sari, ‘Blurred Lines: Hybrid Threats and the Politics of International Law’, January 2018, Back
5 T.M. Franck, ‘The Power of Legitimacy and the Legitimacy of Power: International Law in an Age of Power Disequilibrium’, Vol. 100 A.J.I.L. 2006, pp. 88-106, 91. Back


'institutionalist' approach in their interactions with other international subjects. 6 At present, however, we do not experience a serious extended reaction against the interpretation of the world order as portrayed in the NSS. Rather, other world powers like Russia are revising their foreign political strategies in line with the American one. 7 This means that, logically, if major powers decide to become more aggressive and competitive, most likely, less powerful States will be soon forced to follow the same trend, with a view of simply trying to survive.

In Section III, a possible definition of espionage is presented in more detail, and adjusted to reflect modern techniques and practices, providing the theoretical grounds on which the following analysis is founded. The latter is developed in the subsequent two sections.

In Section IV, the potential legality of espionage is investigated by having regard to: a) the end of the war/peace dualism (Sub-Section 1); b) the de facto identity of the legal regime of espionage in both peacetime and wartime (Sub-Section 2); and c) the existence of a customary law rule (Sub-Section 3). The analysis is circumscribed to state-sponsored espionage for national security purposes, including cases of espionage conducted by States against foreign companies located abroad. The study does not consider industrial espionage carried out by companies against possible foreign private competitors.

In Section V, the conduct of espionage activities is balanced with a number of possible conflicting obligations for the spying State (Sub-Section 1), arising out of human rights law (Sub-Section 2), the principle of sovereignty (Sub-Section 3), the prohibition of intervention in internal affairs (Sub-Section 4), and the immunity of diplomatic missions (Sub-Section 5). The purpose is to demonstrate that espionage may be held lawful even in presence of conflicting obligations for the spying State, depending on the circumstances of the case. The obligations reported in Section V are the most common obligations that espionage ends up interfering with. We understand that the list of possible conflicting obligations is much longer, but the aim of this article is not to address all possible conflicts of norms and obligations. Rather, the article’s scope is to show that espionage may be deemed lawful even in presence of conflicting obligations for the spying State. In addition, it is perhaps worth specifying that this article considers the principle of sovereignty as a primary international law rule, the violation of which should result in international legal responsibility. The recent contrary positions expressed by the UK Attorney General and the General Counsel of the US Department of Defence on the matter reinforce the feeling that in this historical moment major powers prefer having carte blanche when it comes to the conduct of non-coercive non-physical intrusion operations in foreign States. 8

The article’s final section (Section VI) includes some provisional conclusions concerning the possible consequences of legalizing state-controlled espionage at the international level.

In the author’s auspices, this study should provoke a debate among scholars and practitioners on the issue of the potential legality of espionage in the modern international scenario and its limits. Several of the theories expressed in this article are still open to discussion and possibly not always accepted by the majority of scholars. However, these are exactly the most appropriate theoretical premises to start a debate. Any legal theory evolves with dialectic confrontation.

6 For a comprehensive description of the liberal and the institutionalist agendas - as emerged in the early 1990s - see e.g. A-M. Slaughter, ‘International Law and International Relations Theory: A Dual Agenda’, Vol. 87 A.J.I.L. 1993, pp. 205-239. Back
7 See I. Facon, ‘Russia’s National Security Strategy and Military Doctrine and Their Implications for the EU’, 1 February 2017, ‘The [most recent Russian] strategic documents emphasize the Russian leaders’ vision that the international scene is dangerous, volatile, chaotic, and marked by stiff competition for resources (including, supposedly, Russia’s), control of markets and transport routes, and political influence amongst major powers’. Back
8 See infra, Section V(3). Back


II. The Age of Permanent Competition According to the New US National Security Strategy

The New US National Security Strategy (NSS) was presented to the public on 18 December 2017. 9 The document is meant to reflect the new US Administration’s leading principle in foreign affairs, i.e. the so-called ‘principled realism’. Based on this tenet, ‘American principles are [conceived as] a lasting force for good in the world’ 10 , and therefore they need to be pursued by the US in the international arena in any manner whatsoever. Since the new NSS draws extensively on the traditional theory of political realism, unsurprisingly, it also frequently refers to ‘competition’ to explain the present international scenario. 11 In US President Trump’s words, ‘[w]hether we like it or not, we are engaged in a new era of competition’. 12 According to the US government, ‘[c]ompetition does not always mean hostility’, 13 however, the present international scenario sees adversaries and competitors misusing the (legitimate) principle of competition to obtain unfair gains to the detriment of the US, by ‘operating below the threshold of open military conflict and at the edges of international law’. 14 Notably, according to the NSS, this deceitful approach could even reach the point of making the traditional peace/war dichotomy obsolete, as the US would now be ready ‘to raise [their] competitive game’ 15 in response to such unfair practices, so that, basically, all options would eventually be on the table.

As it was brilliantly noted, ‘the idea that war and peace are relative points on a continuous spectrum of confrontation, rather than mutually exclusive conditions, has become quite popular in recent years’, 16 and stands at the heart of concepts such as the ‘grey zone conflict’ and the ‘hybrid warfare’, which are gaining momentum in military doctrine and academic literature. 17 Under this perspective, armed and non-armed confrontation, rather than cooperation towards common interests, 18 has now become the rule and not the exception among the most powerful

9 The White House, ‘National Security Strategy of the United States of America’, December 2017, . Back
10 Id. p. 1. Back
11 Id. pp. 2-3. Back
12 Quoted in C. Wilkie, ‘Trump Unveils a National Security Strategy that Reflects “America First” Campaign Pledge’, 18 December 2017, . Back
13 NSS, supra note 9, p. 3. Back
14 Id., p. 27. Back
15 Id., p. 28:
‘The United States must prepare for this type of competition. China, Russia, and other state and nonstate actors recognize that the United States often views the world in binary terms, with states being either “at peace” or “at war,” when it is actually an arena of continuous competition. Our adversaries will not fight us on our terms. We will raise our competitive game to meet that challenge, to protect American interests, and to advance our values’. Back
16 A. Sari & A. Lauva, ‘Hybrid Threats and the United States National Security Strategy: Prevailing in an “Arena of Continuous Competition”’, 19 January 2018, . The authors refer to some recent speeches given by the Chief of the General Staff of the Russian Federation, the former British Secretary of State for Defence and NATO’s Secretary General. See also Fleck, who postulates that ‘[s]trict adherence to the dichotomy between war and peace would be ineffective and counterproductive for establishing peace and security’ (D. Fleck, ‘Individual and State Responsibility for Intelligence Gathering’ Vol. 28 Michigan J.I.L. 2007, pp. 687-709, 690). Back
17 According to a 2015 US Special Operations Command’s White Paper, ‘gray zone challenges [may be] defined as competitive interactions among and within state and non-state actors that fall between the traditional war and peace duality’: United States Special Operations Command, ‘The Gray Zone’, 9 September 2015, Zones - USSOCOM White Paper 9 Sep 2015.pdf . According to Hoffman, in hybrid warfare ‘the adversary will most likely present unique combinational or hybrid threats specifically targeting U.S. vulnerabilities. Instead of separate challengers with fundamentally different approaches (conventional, irregular, or terrorist), we can expect to face competitors who will employ all forms of war and tactics, perhaps simultaneously’, including criminal activities (F.G. Hoffman, ‘Hybrid Warfare and Challenges’, Vol. 52(1) Joint Force Quarterly 2009, pp. 34-48, 35. See also A. Sari, ‘Hybrid Warfare, Law and the Fulda Gap’, in W.S. Williams and C.M. Ford (eds), Complex Battle Spaces: The Law of Armed Conflict and the Dynamics of Modern Warfare (Oxford, OUP, 2019, forthcoming)). Interestingly, at the time of the ‘colour revolutions’ in Eastern Europe, it was Russia who accused the US to have been the target of a hybrid conflict launched by Washington (see R. Thornton, ‘The Changing Nature of Modern Warfare’, 160 RUSI Journal 2015, pp. 40-48, 42). Back
18 The new NSS contains a nuanced theory of cooperation with competing nations, according to which, ‘[t]he United States will seek areas of cooperation with competitors from a position of strength, foremost by ensuring [their] military power is second to none and fully integrated with [their] allies and all of our instruments of power’ (NSS, supra note 9, p. 26). Back


nations. Nonetheless, the legal contours of this confrontation, or better its legitimacy in light of existing international law norms, has still to be comprehensively addressed. 19

In this worldwide quest for power, the role of information seems pivotal. Notably, the NSS mentions the power of information as one of the key elements to reach and maintain supremacy over competing international actors. 20 But, again, if the goal – a goal which is deemed lawful by the most powerful State in the world – turns out to be that of achieving and preserving the power of information through competition, what practices or instruments may States legitimately use to accomplish it? In a condition of permanent competition, one may assume that States would strive to protect all information in their possession that might grant them a competitive advantage over other States. The latter would in turn attempt to breach any defensive measures put in place by the former in order to get this information, being otherwise destined to succumb. Can anyone say that this constitutes an unlawful conduct? Or should these ‘unprivileged States’ simply surrender to ‘privileged States’? This conduct has a name. It is called espionage.

III. A Modern Definition of Espionage

Espionage is often called ‘the world’s second-oldest profession’, 21 to describe the attitude of kingdoms, empires and States to spy on each other over the millenniums. The intelligence function has been defined as an essential part of any State policy or decision-making process, 22 and nowadays it is exercised by States against both adversaries and friends. 23 Notwithstanding its

19 In truth, when reflecting on this topic, scholars often limit their analysis to the legality of armed responses to ‘non-forcible attacks’, in accordance with the principle of self-defence under the UN Charter. See in particular the international legal discourse on the response in self-defence to the use of computer network attacks or cyberwarfare in M.N. Schmitt (ed), Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations (Cambridge, CUP, 2017) p. 339. See also Sari & Lauva (supra note 16)). This topic is indeed extremely relevant to the evolution of the theories surrounding the concept of jus ad bellum, but, here, the use of force represents a mere reaction to an act equivalent to a (supposedly wrongful) armed attack. There may be – and in fact there are – internationally wrongful acts not amounting to an armed attack – at least not clearly – which are nonetheless a clear sign of hostility, as – for instance – in the case of an intervention by a State in the internal affairs of another State (see the definition of ‘intervention’ in ICJ, Military and Paramilitary Activities in and Against Nicaragua (Nicaragua v. US), 27 June 1986, I.C.J. Rep. 1986, p. 96, § 202). In theory, any legitimate countermeasure to such acts should not entail the use of force (ILC, Draft Articles on Responsibility of States for Internationally Wrongful Acts, with Commentaries, UN Doc A/56/10, Vol. II(2) Yearbook of the I.L.C. 2001, p. 132 (Commentary to Article 50) [hereinafter ARSIWA]). In addition, even when not intervening in the internal affairs of another State, a State may nonetheless attempt to impair the former State’s policies at the international level using ‘unfair’ – but not internationally wrongful – practices, if these policies are contrary to its interests. For instance, the NSS labels China’s current trade and economic practices as ‘unfair’. In response, the US will work with its partners to contest these practices and restrict China’s acquisition of sensitive technologies (NSS, supra note 9, p. 48). Back
20 NSS, supra note 9, p. 3:
‘The contest over information accelerates […] political, economic, and military competitions. Data, like energy, will shape U.S. economic prosperity and our future strategic position in the world. The ability to harness the power of data is fundamental to the continuing growth of America’s economy, prevailing against hostile ideologies, and building and deploying the most effective military in the world.’ Back
21 S. Chesterman, ‘The Spy who Came in from The Cold War: Intelligence and International Law’, Vol. 27 Michigan J.I.L. 2006, pp. 1071-1130, 1072. Back
22 G.B. Demarest, ‘Espionage in International Law’, Vol. 24 Denver Journal International Law and Policy 1996, pp. 321-348, 321; D. Pun, ‘Rethinking Espionage in the Modern Era’, Vol. 18 Chicago Journal of International Law 2017, pp. 353-391, 357-358; M.E. Bowman, ‘Intelligence and international law’, Vol. 8 International Journal of Intelligence and CounterIntelligence 1995, pp. 321-335, 327. Back
23 As Lord Palmer – former British Prime Minister – argued in 1848 in a famous speech before the House of Commons: ‘We have no eternal allies and we have no perpetual enemies. Our interests are eternal and perpetual, and those interests it is our duty to follow’ (Sir Henry Temple, 3rd Viscount Palmerston, quoted in E. Heath, ‘Realism in British Foreign Policy’, Vol. 48(1) Foreign Affairs 1969, pp. 39-50, 39). The same realist rationale we may find in a recent interview of a former member of the French Directorate-General for External Security (DGSE), who highlighted how, even in the relationships among Western States, ‘there are no friends, there are only allies’ (Mr Arnaud Danjean, quoted in J. Follorou, ‘“Tous les services de renseignement occidentaux s'espionnent”’, 4 July 2013, [original quote: ‘Tous les services de renseignement occidentaux s'espionnent. Il n’y a pas d’amis, il n’y a que des alliés’]. Likewise, the former President of the Italian Republic, Francesco Cossiga, was quoted to have said that the favourite target of intelligence activities are precisely friends and allies, rather than opponents (quoted by Professor Mario Caligiuri in Askanews, ‘Caligiuri: spionaggio tra alleati è la norma’, 8 March 2017, . Back


diffusion, circumscribing the meaning of modern espionage in a single definition is not an easy task.

A definition of ‘espionage’ which is frequently cited in the international legal literature is that of the US Army officer Geoffrey B. Demarest, according to which ‘espionage can be defined as the consciously deceitful collection of information, ordered by a government or organization hostile to or suspicious of those the information concerns, accomplished by humans unauthorized by the target to do the collecting’. 24 This definition restricts the field of analysis. Under this definition, the collection of information must indeed be somewhat fraudulent and without consent. Moreover, it has to be carried out by an individual who knows what he/she is doing, and who is mandated by a government (or an organisation). This definition excludes practices such as intelligence gathering from open sources (OSINT). 25 Demarest’s, definition of ‘espionage’ also excludes any form of ‘technical’ intelligence gathering, as the latter is not characterised by personal deceit. 26 Indeed, Demarest’s definition largely resembles that of ‘human intelligence’ (HUMINT). 27 In fact Demarest coined this definition in 1996, basing it on the definition of ‘spy’ in the Soviet Union and the US’s domestic law/jurisprudence and, partially, the international law of armed conflict (LOAC). 28 Such a cold-war-inspired definition of ‘espionage’ therefore risks not reflecting entirely the current alleged end of the peace/war dichotomy in international relations; hence it is not fit for our purposes. Actually, since nowadays signals intelligence (SIGINT) 29 or geospatial intelligence (GEOINT) 30 dominates over HUMINT, the material element of deception seems less relevant in describing the reality of contemporary spying.

There are other issues that need to be considered, inter alia, in defining modern espionage. In the first instance, espionage does not necessarily encompass only classified information. In the age of permanent competition, vital information for a State does not need to be a State secret for the competing State or be held directly by the latter. Private firms located in one State may easily develop research or commercial products that may be important or even essential for a competing State. What is relevant is the significance of this information to win the competition or achieve a position of strength and the fact that this information is not publicly available. In legal terms,

24 Demarest, supra note 22, pp. 325-326. Back
25 For a definition of OSINT see E.A. Jardines, ‘Open Source Intelligence’, in M.M. Lowenthal & R.M. Clark (eds), The Five Disciplines of Intelligence Collection (Thousand Oaks, CQ Press, 2016), pp. 5-44, 5. Back
26 Demarest, supra note 22, pp. 338 and 347. Back
27 HUMINT is the kind of intelligence collection which ‘is usually associated with espionage or the clandestine acquisition of secrets by a human source […]. The fundamental elements are the clandestine method of collection, the secret nature of the material collected, and most importantly the human collector. […] [O]nly HUMINT utilizes people as its source’ (M. Althoff, ‘Human Intelligence’, in Lowenthal & Clark, supra note 25, pp. 45-80, 45). Back
28 Demarest, supra note 22, pp. 326 and 331-337. See in particular the 1874 Declaration of Brussels Concerning the Laws and Customs of War, art. 19, the 1907 Hague Regulations, art. 29, the 1923 Hague Rules of Air Warfare, art. 27, and the 1977 AP I, art. 46. Back
29 ‘SIGINT is a form of intelligence derived from the collection and processing of various forms of electronically transmitted data and information; those forms being the communication of human language material […]; and data derived from electronic emission devices, primarily radar […]’ (W.N. Nolte, ‘Signals Intelligence’, in Lowenthal & Clark, supra note 25, pp. 81-110, 81). Back
30 GEOINT ‘means the exploitation and analysis of imagery and geospatial information to describe, assess, and visually depict physical features and geographically referenced activities on the earth. [It] consists of imagery, imagery intelligence, and geospatial information (D. Murdock & R.M. Clark, ‘Geospatial Intelligence’, in Lowenthal & Clark, supra note 25, pp. 111-158, 111). Back


however, under the principle of territoriality, spying on a private firm has the same consequences as spying on the territory of the State where the firm is based. 31

As the passive subject of espionage can be a private legal or natural person, the same holds true for the active subject. A government could simply not possess the necessary expertise to conduct a specific spying operation or could prefer outsourcing the operation to a private contractor for financial or political reasons. 32 Irrespective of their private status, by acting under the direction, instigation or control of organs of government, contractors would be considered as State agents and their conduct would anyway be attributed to the controlling State. 33

A more recent – and less refined – definition of espionage (by cyber capabilities) is the one reported in the Tallinn Manual 2.0:
‘“[C]yber espionage” refers to any act undertaken clandestinely or under false pretences that uses cyber capabilities to gather, or attempt to gather, information. Cyber espionage involves, but is not limited to, the use of cyber capabilities to surveil, monitor, capture, or exfiltrate electronically transmitted or stored communications, data or other information.’ 34
Here the element of deception is alternative to that of secrecy, 35 and indeed, nowadays, secrecy, rather than deception, represents the key factor of a spying operation. Moreover, the human factor disappears, as information gathering can be performed (and it is in fact often performed) entirely by computers, based on pre-set algorithms. 36 OSINT, instead, continues to be excluded.

Starting from the definition reported in the Tallinn Manual 2.0, and eliminating all specific references to cyber capabilities, the definition of espionage could sound as follows: ‘“Espionage” refers to any act undertaken clandestinely or under false pretences by State agents or contractors that uses appropriate capabilities to collect, or attempt to collect, information. Espionage involves the use of appropriate capabilities to surveil, monitor, capture, or exfiltrate communications, data or other information’. This wide, generic and non-technical definition nonetheless excludes ‘private espionage’, 37 which remains confined to the mere domestic or transnational sphere, in the

31 See mutatis mutandis W. Heintschel von Heinegg, ‘Legal Implications of Territorial Sovereignty in Cyberspace’, in C.C. Czosseck, R. Ottis & K. Ziolkowski (eds), 2012 4th International Conference on Cyber Conflict (Tallinn, NATO CCD COE Publications, 2012), pp. 7-19, 12. Back
32 Outsourcing intelligence services is a common practice in the US. Outsourced intelligence services represent about 70 percent of the whole US intelligence budget, for roughly $50 billion-a-year (see on the matter T. Shorrock, Spies for Hire: The Secret World of Intelligence Outsourcing (New York, Simon & Schuster, 2008). According to Shorrock, five big companies would compete for the US intelligence market (T. Shorrock, ‘5 Corporations Now Dominate Our Privatized Intelligence Industry’, 8 September 2016, ) . The phenomenon is not restricted to the US, though. For example, in Romania, at the end of the ‘90s, there were reportedly about 160 private intelligence agencies run by former State security/intelligence personnel (K.A. O’Brien, ‘What should and what should not be regulated?’, in S. Chesterman & C. Lehnardt (eds), From Mercenaries to Market: The Rise and Regulation of Private Military Companies (Oxford, OUP, 2007), pp. 29-48, 38). There is a large amount of literature on the topic of privatized intelligence. See for instance: H. Bean, ‘Privatizing intelligence’, in R. Abrahamsen & A. Leander (eds), Routledge Handbook of Private Security Studies (Abingdon, Routledge 2016), pp. 79-88; and P.R. Keefe, ‘Privatized Spying: The Emerging Intelligence Industry’, in L.K. Johnson (ed), The Oxford Handbook of National Security Intelligence (Oxford, OUP, 2010), pp. 296-309. Back
33 ARSIWA, supra note 19, p. 47 (Commentary to art 8). Back
34 Tallinn Manual 2.0, supra note 19, p. 168. Back
35 Indeed, all the norms of the law of armed conflict considered by Demarest mention such elements in alternative (see supra note 28). Back
36 See e.g. the ECHELON global communications monitoring system – run by the ‘Five Eyes’ (US, UK, Canada, Australia and New Zealand), which is based on the automatic recognition of specific keywords (see EU Parliament - Temporary Committee on the ECHELON Interception System, Report on the existence of a global system for the interception of private and commercial communications (ECHELON interception system), 11 July 2001, EU Doc 2001/2098(INI)). Back
37 ‘Private espionage’ can be considered as the clandestine or deceitful collection of information carried out by legal or natural persons acting privately, for instance for economic or moral purposes. See e.g. the case of WikiLeaks, an international non-profit, ‘non-territorial’, organisation, that publishes secret information, news leaks, and classified media provided by anonymous sources: . The private character of espionage does not cease to exist in the case the target of a spying activity by a private firm is a State or a public organ. See e.g. the alleged spying by Kroll Inc. (an international security firm based in the US, who denied all accusations) of two Brazilian government officials (i.e. the then minister of communications and the then president of the bank of Brazil) in 2004, as a part of a wider confrontation over the control of Brasil Telecom between Telecom Italia and Brazil's Opportunity Bank (T. Benson, ‘Police Raid Kroll Offices in Brazil’, 28 October 2004, ) . Back


context of privacy law, commercial law or criminal law. 38 Yet, it encompasses any possible capabilities, including the use of satellites.

Under the aforesaid definition, the concept of espionage is to be kept separate from that of ‘covert action’. 39 Covert action may in fact include far more intrusive conducts than espionage and comprise of activities such as psychological or information operations (or even ‘kinetic operations’ 40 ), which have nothing to do with the mere collection of information. In covert action, the operation’s goal is to influence/coerce the target’s will/conduct and not to collect information from it. Nonetheless, espionage may constitute a preparatory or supporting activity to covert action.

That being said, if States are bound to compete and induced or forced to resort to espionage, as defined above, it remains to be seen whether they can do it within the boundaries of law.

IV. May Espionage Outside an Armed Conflict be Held Legal Under International Law?

1. Espionage is Legal Due to the End of the War/Peace Dualism

Espionage in the course of an international armed conflict is generally held lawful under LOAC. 41 The latter, however, does not protect spies from prosecution, if they are captured before they have re-joined the armed forces to which they belong. 42 Prosecution is limited to the captured spies and does not extend to their hierarchical line within the enemy forces. In practice, criminal liability is bizarrely confined solely to the ultimate perpetrator. In addition the spies’ possible criminal liability does not generate the sending State’s international responsibility, 43 and this – again – can be interpreted as a clear sign of the legality of wartime espionage under international law.

Interestingly, some scholars observe that the legality of wartime espionage stems from the necessity of carrying out reconnaissance operations, 44 to both spare civilians during attacks and

38 For instance, depending on the domestic legal system of reference, to be lawful the use of ‘competitive intelligence’ or ‘marketplace intelligence’ – that concerns the practice of private firms/enterprises to gather intelligence on possible competitors – should be based solely on OSINT (A.S. Hulnick, ‘The Dilemma of Open Sources Intelligence: Is OSINT Really Intelligence?’, in Johnson, supra note 32, pp. 229-241, 231). Back
39 Under US law, the two concepts are kept distinct. According to the US Code, ‘covert action’ is defined as:
‘an activity or activities of the United States Government to influence political, economic, or military conditions abroad, where it is intended that the role of the United States Government will not be apparent or acknowledged publicly, but does not include (1) activities the primary purpose of which is to acquire intelligence’ (50 US Code § 3093 (e)).
Professor Perina defines ‘covert action’ as an ‘unacknowledged operation […] intended to influence events in another country, conducted by any [S]tate agency or actor, or other entity acting on behalf of a [S]tate’ (A.H. Perina, ‘Black Holes and Open Secrets: The Impact of Covert Action on International Law’, Vol. 53 Columbia Journal of Transnational Law 2015, pp. 507-583, 510). Back
40 According to Stephen W. Preston, former CIA General Counsel, the US Special Forces raid to capture Osama Bin Laden may be included within the context of a covert action (CIA, Remarks by CIA General Counsel Stephen W Preston as prepared for delivery at Harvard Law School, 10 April 2012, . According to Professor Richard Baxter (former judge at the ICJ and former professor of international law at Harvard Law School), there is ‘virtual unanimity of opinion that […] some, and probably all, spies [in an armed conflict] do not violate international law’ (quoted in Fleck, supra note 16, p. 689). According to General Hallbeck (Commander of all Union armies during the American Civil War), ‘[t]he employment of spies is no offense against the laws of war, and it gives to the enemy no cause of complaint’ (H.W. Hallbeck, ‘Military Espionage’, Vol. 5 A.J.I.L. 1911, pp. 590-603, 593). Back
42 AP I, art. 46(4). Back
43 J. Stone, ‘Legal Problems of Espionage in Conditions of Modern Conflict’, in R.J. Stanger (ed), Essays on Espionage and International Law (Columbus, Ohio State University Press 1962), pp. 29-43, 33. Back
44 J. Kish (D. Turns, ed), International Law and Espionage (The Hague, Martinus Nijhoff, 1995), p. 155. Back


protect State security. Gathering information on the enemy in secret, through deception or under false pretences is therefore acknowledged as essential to the conduct of military operations. Here the term ‘necessity’ is not to be held as a condition precluding the wrongfulness of an otherwise unlawful conduct under international law. States use wartime espionage as a common means of warfare, not as an extrema ratio ‘to safeguard an essential interest against a grave and imminent peril’. 45 For this reason, the necessity to gather information in times of conflict is to be traced back to the concept of ‘military necessity’. 46 In this sense, espionage would basically represent nothing but a ‘measure […] by [a belligerent] necessary to protect the safety of his forces and to facilitate the success of his operations’. 47

Notably, however, an international armed conflict is nothing but the hardest kind of legally-possible confrontation, or competition, among States. If – as hinted in the NSS – worldwide competition has nowadays become the international relations’ natural status and the war/peace dualism has dissolved into a kind of permanent world-wide hybrid low-intensity conflict, the same rationale that justifies espionage in full-scale conflicts could apply to this new kind of conflicting situation as well. In practice, the concept of military necessity would be replaced with the necessity of States to survive global competition. Spying outside a clear armed confrontation could be now legally based on the necessity of States ‘to protect the safety of their citizens and to facilitate the success of their competing practices’. In this perspective, the raison d'être of espionage in times of conflict could develop into a permanent standard justification for any spying activities carried out anytime, anywhere.

2. The Legality of Espionage is the Same in Both Peace and War

The same conclusion, namely that both peacetime and wartime espionage share the same level of legality under international law, 48 can be reached also without using the argument of the end of the peace/war dualism.

The potential legality of peacetime espionage has been assessed in depth in the legal literature. 49 Since the 1960s, scholars have often argued that in peacetime international law is simply ‘neutral’ 50 in respect of espionage, or that espionage is an extra-legal phenomenon. 51 Undeniably, no positive international law rules authorise espionage in times of peace, nor can such rules be

45 ARSIWA, supra note 19, p. 80 (Commentary to art 25). Back
46 On the concept of ‘military necessity’ see Y. Dinstein, ‘Military Necessity’, in F. Lachenmann & R. Wolfrum (eds), The Law of Armed Conflict and the Use of Force: The Max Planck Encyclopedia of Public International Law (Oxford, OUP, 2017), pp. 710-716, 710. Back
47 This definition of ‘military necessity’ is taken from the definition adopted by the Nuremberg Tribunal in the so-called ‘Hostage Case’ of 1948 (United States of America v. Wilhelm List et al., 19 February 1948, Case No. 7, XI, 1253, ) . Back
48 In a 1991 decision on an espionage case involving the chief of the former DDR Central Detection Agency, the Federal Supreme Court of Germany specified that ‘in both wartime and peacetime [espionage] is considered a “lawful behaviour” under international law’ (Federal Supreme Court of Germany (BGH), 30 January 1991, Case No. 2 BGs 38/91, Vol. 94 I.L.R. 1994, pp. 68-82, 74 [Espionage Prosecution Case]). Back
49 A.J. Radsan, ‘The Unresolved Equation of Espionage and International Law’, Vol. 28 Michigan J.I.L. 2007, pp. 595-623, 602; K. Ziolkowski, ‘Peacetime Cyber Espionage – New Tendencies in Public International Law’, in K. Ziolkowski (ed), Peacetime Regime for State Activities in Cyberspace (Tallinn, NATO CCD COE Publications, 2013), pp. 425-464, 430-431. In both articles the authors make an in depth survey of the existing scholarship on each position. Some of the citations reported in the following footnotes also appear in these two publications. Back
50 Professor Richard Falk, in a foreword to a famous 1962 edited collection of essays on espionage, uses the term ‘oblivious’ to denote the character of international law towards peacetime espionage (R. Falk, ‘Foreword’, in Stanger, supra note 43, pp. i-ix, v). Back
51 See e.g. C.D. Baker, ‘Tolerance of International Espionage: A Functional Approach’, Vol. 19 American University International Law Review 2003, 1091-1113. According to Professor Radsan, ‘[t]he only consensus that exists concerning espionage is that sometimes it is right and sometimes it is wrong; it all depends on the circumstances’ (Radsan, supra note 49, p. 611). Back


inferred by analogy from other rules. 52 Nonetheless, under the scholarly point of view, this opinion appears unsatisfactory and somewhat ‘pilatesque’. Can such a common practice of international relations be excluded from the realm of international law? Moreover, ‘neutrality’ does not necessarily imply ‘legality’ and, therefore, the latter has to be defined otherwise.

Looking at the legal scholarship, some scholars hold espionage as a lawful measure – or better, not contrary to customary international law. 53 Others, on the contrary, consider it illegal. 54 Alternatively, some scholars posit the legality of espionage only when conducted in spaces beyond the States’ sovereignty, such as the outer space 55 and international waters, 56 including foreign exclusive economic zones, 57 based on the principle of free use of such spaces. 58 Others come to the point of affirming that espionage has a specific legal basis in international law, by relying on the principle of State sovereignty 59 , or by associating the legality of spying to other norms or principles of international law (for instance, the principle of self-defence 60 ) and the necessity to keep a balance of power among nations for the sake of peace. 61 Other scholars, again, refer to espionage as an inevitable practice associated to treaty-based obligations concerning arms control 62 or conflict prevention. 63

Distinct from the legality at the international level is the legality of espionage in the States’ domestic legal systems. Here the crime of espionage is punished virtually in all the countries of the world. Nonetheless, in recent years, the same countries that so readily punish espionage conducted by foreign States against them, have also increasingly regulated, through statutes, the collection of information by their intelligence services. 64 This – in practice – results in publicly

52 According to the German Constitutional Court, ‘[n]o international agreement had ever been concluded on the subject [of peacetime espionage]. Neither was there any usage sufficient to establish a customary rule permitting, prohibiting or otherwise regulating such activity’ (BGH, supra note 48, p. 70). Back
53 M. Roscini, ‘Cyber Operations as Nuclear Counterproliferation Measures’, Vol. 19 J.C.S.L. 2014, pp. 133-157, 139; R.D. Scott, ‘Territorially Intrusive Intelligence Collection and International Law’, Vol. 46 Air Force Law Review 1999, pp. 217-226; Tallinn Manual 2.0, supra note 19, p. 169; Demarest, supra note 22, p. 347; Bowman, supra note 22, p. 328. Back
54 Q. Wright, ‘Espionage and the Doctrine of Non-intervention in Internal Affairs’, in Stanger, supra note 43, pp. 3-28. According to Professor Wright, peacetime espionage would undermine the States territorial integrity and political independence (Id., p. 12). See also M.R. Garcia-Mora, ‘Treason, Sedition and Espionage as Political Offenses Under the Law of Extradition’, Vol. 26 University of Pittsburgh Law Review 1964-1965, pp. 65-97. Back
55 Stone, supra note 43, p. 34; Kish & Turns, supra note 44, p. 120; Chesterman, supra note 21, p. 1085. Back
56 J. Kraska, ‘Putting Your Head in the Tiger’s Mouth: Submarine Espionage in Territorial Waters’, Vol. 54 Columbia Journal of Transnational Law 2015, pp. 164-247, 174; Scott, supra note 53, p. 219. Back
57 E. Papastavridis, ‘Intelligence Gathering in the Exclusive Economic Zone’, Vol. 93 International Legal Studies 2017, pp. 446-475, 475. Back
58 Notably, these spaces should in theory be used exclusively ‘for peaceful purposes’ (see UNCLOS, art. 88 and the works of the UN Committee on the Peaceful Uses of Outer Space (COPUOS) ). Back
59 According to Professor Sulmasy and Professor Yoo, ‘most experts today still agree that espionage remains part of the sovereign right of the nation-state’ (G. Sulmasy and J. Yoo, ‘Counterintuitive: Intelligence Operations and International Law’, Vol. 28 Michigan J.I.L. 2006, pp. 625-638, 628). Back
60 A.S. Deeks, ‘Confronting and Adapting: Intelligence Agencies and International Law’, Vol. 102 Virginia Law Review 2016, pp. 599-685, 610; Scott, supra note 53, p. 224; Wright, supra note 54, p. 16. Back
61 Wright, supra note 54, p. 19. Back
62 R.J. Stanger, ‘Espionage and Arms Control’, in Stanger, supra note 43, pp. 83-101, 84; Stone, supra note 43, p. 44. Back
63 Baker, supra note 51, p. 1104; Scott, supra note 53, p. 223. Bitton bases the legality of espionage on the existence of a ‘duty of basic transparency about strategic intentions’ among States (R. Bitton, ‘The Legitimacy of Spying Among Nations’, Vol. 29 American University International Law Review 2014, pp. 1009-1070, 1030). Back
64 In April 2016, the law firm ‘Baker & McKenzie’ compiled a ‘Global Surveillance Law Comparison Guide’ which provides a global overview of current government surveillance and data access practices in 39 countries in the world: . See also Tallinn Manual 2.0, supra note 19, p. 169, and Deeks, supra note 60, p. 624. Professor Deeks, who proposes the creation of an international legal framework for espionage, also highlights the increasing ‘legalisation’ of national intelligence services, which are now reportedly staffed with a growing number of lawyers as a result of the adoption of a growing number of domestic statutes on the regulation of intelligence services (Id. ). Back


admitting that they may lawfully resort to espionage and that espionage is to be exercised under specific legal boundaries. Interestingly, for some States these boundaries include international law rules. 65 This apparent contradiction – which sees States punishing foreign espionage and legitimising their own – reflects the same paradigm applied by States in wartime.

Similarly to what happens in peacetime, no positive international law rules authorize espionage in times of war. LOAC treaty norms consider espionage only when defining the term ‘spy’. 66 In addition, the notion of ‘spy’ is presented exclusively in negative terms, i.e. a spy can be punished for collecting information – that is, basically, participating in hostilities – while a privileged combatant cannot. In addition, according to LOAC, prosecution of spies is merely potential since it is the capturing State’s choice to decide whether or not to punish a spy after his/her capture, 67 as espionage is definitely not an international crime. Since – under LOAC – spies are to be granted a ‘fair and regular trial’, 68 the status and treatment of spies ends up being regulated in domestic criminal law only, i.e. exactly like in the case of ‘peacetime’ espionage.

On a separate note, it may also be observed that this definition of spy, included in LOAC, is clearly old-fashioned, as it only concerns conducts undertaken while the agent is physically present in the ‘enemy-controlled territory’. 69 With the triumph of de-territorialised intelligence activities (SIGINT and GEOINT) outsourced to civilian contractors, the agent’s physical location or his/her attire have become much less characterising factors. Apart from this, the existence of norms on the definition or status of spies in LOAC is of little use in affirming the legality of espionage. It is not because LOAC acknowledges the existence of espionage during armed conflicts that espionage itself is automatically to be considered a lawful practice. Quite the contrary, since spies may be lawfully punished, one should assume that their conduct is in principle unlawful, at both domestic and international level. Nonetheless, the legality of wartime espionage has never been questioned.

In the absence of specific treaty norms, one option is to assert the legality of wartime espionage by referring to the lack of a norm that prohibits it – i.e. by applying the famous Lotus rule. 70 However, the same would hold true for peacetime espionage, where the absence of an explicit prohibition may be read as a way to claim its legitimacy. 71 In brief, by applying the Lotus rule, if one assumes that espionage is legal in wartime, one is obliged to conclude that it is legal in peacetime as well.

3. Espionage is Legal Under Customary Law

A second option – additional to that based on the Lotus dictum – could be that of considering the formation of a customary law rule 72 that would allow espionage in both wartime and peacetime.

65 Indeed the UK has explicitly declared that international law applies to its intelligence activities. For its part, the US has publicly affirmed that these activities comply with several bodies of international law as a matter of policy (Deeks, supra note 60, p. 650). Back
66 See supra note 28. Back
67 No specific LOAC provision prescribes prosecution. LOAC simply allows the prosecution of spies. See e.g. Geneva Convention IV, art. 5: ‘A spy […] shall nevertheless be treated with humanity, and in case of trial [italics added], shall not be deprived of the rights of fair and regular trial’. Back
68 Id. art. 30 of the 1907 Hague Regulations includes the same principle: ‘A spy taken in the act shall not be punished without previous trial’. Back
69 This is the term used in the Tallinn Manual 2.0 to encompass both the ‘territory controlled by an adverse party’ and ‘zone of operations of a belligerent’, under AP I, art. 46 and Hague Regulations, art. 29 respectively (Tallinn Manual 2.0., supra note 19, p. 411). Back
70 The famous Lotus rule affirms that, in the absence of an explicit prohibition, ‘every State remains free to adopt the principles which it regards as best and most suitable’ (PCIJ, SS Lotus (France v. Turkey) , 1927 P.C.I.J. (Series A) No. 10, 7 September 1927, p. 19). Back
71 Interestingly, by applying a Lotus-driven-non-liquet reasoning, one could argue that in the case of espionage, the States’ consent is necessary to prohibit at the international level an activity which is already prohibited at the national level, also taking into account that such activity is performed to their benefit (F. Lafouasse, ‘L’espionnage en droit international’, Vol. 47 Annuaire français de droit international 2001, pp. 63-136, 136). Back
72 Baker, supra note 51, pp. 1094-1095. Back


In peacetime, the fact that States have always resorted to espionage (practice), coupled with the increasing regulation of intelligence activities under national law (opinio iuris), may be deemed to be the key elements that determine the existence of a custom, 73 by applying a deductive method. 74 Inter alia, the opinio juris could be deduced by publicly-disclosed-espionage-related agreements among States, such as those on the exchange of captured spies, 75 the sharing of intelligence information collected through espionage, 76 or even the regulation of economic espionage. 77 If espionage were illegal under international law, it would not be the object of international legal or political obligations. This argument may also help in overcoming the theory on the impossibility of considering secret activities as State practice, which is based, first and foremost, on the condition that, in order to count as State practice, a State act must be communicated to at least one other State or – even better – be public. 78

In the case of wartime espionage, determining the existence of a customary norm might even be easier. The fact that espionage is to be considered a standard means of warfare, is openly acknowledged in the LOAC as well as a multitude of military manuals 79 and State practice. 80 Further to that, wartime espionage has never given rise to any kind of international responsibility claim by the spied States. Again, this could be interpreted as a clear sign of opinio juris.

Another way to examine the legitimacy of espionage under customary law is that of looking at the reaction of States when they find out they have been victims of espionage by other States. 81 Do they publicly affirm the illegality of such practice? In which case, what is their reaction? Do they resort to countermeasures or are they relatively acquiescent? Are spied States silent as to the illegality of spying? True that acquiescence or silence do not necessarily amount to clear evidence of the lack of a breach of international law by the counterpart or the legality of the latter’s conduct, but ‘silence, inaction, tolerance, absence of protest, passivity, and acquiescence can play a very important role in international law and the maxim qui tacet consentire videtur si loqui debuisset ac potuisset is of fundamental importance’ 82 to understand States’ position with regard to specific

73 Deeks, supra note 60, p. 609. Back
74 A deductive method – derived from the approach taken by the ICJ in Nicaragua (supra note 19) – would bypass the obstacle to the definition of State practice on espionage, given the secrecy that covers spying activities (Perina, supra note 39, pp. 571-573). The deductive method is applied in situations – such as that analyzed in Nicaragua by the ICJ – where: a) a court is called to assess, on the one hand, some relevant opinio juris supporting an obligation, and, on the other hand, a numerous contrary practice of States; and b) in cases of a negative practice of States, consisting of abstention and omission (S. Talmon, ‘Determining Customary International Law: The ICJ’s Methodology between Induction, Deduction and Assertion’, Vol. 26 E.J.I.L. 2015, pp. 417-443, 422). Back
75 Kish & Turns, supra note 44, p. 155. Back
76 Chesterman, supra note 21, p. 1099. Back
77 See in particular the 2015 Agreement between the US and China on cybersecurity (The White House, ‘Fact Sheet: President Xi Jinping’s State Visit to the United States’, 25 September 2015, ) . Back
78 International Law Association, Committee on Formation of General Customary International Law, ‘Final Report of the Committee: Statement of Principles Applicable to the Formation of General Customary International Law’ (London: 2000), p. 15, ; ILC, Draft Conclusions on Identification of Customary International Law, with Commentaries, Report adopted by the International Law Commission at its seventieth session, in 2018, and submitted to the General Assembly, UN Doc. A/73/10, p. 133, . Back
79 See the list of IHL provisions in international treaties and domestic manuals compiled by the ICRC: . Back
80 According to Professor Kish and Professor Turns, the US and Russian official positions on the legality of wartime espionage expressed in the second half of 1800 are to be taken as a sign of consensus under customary international law (Kish & Turns, supra note 44, p. 123). Back
81 See a contrario Ziolkowski, according to whom, this rarely happens. In Ziolkowski’s opinion the lack of official assessments as to the legality or illegality of spying activities generates the lack of opinio juris and thus the impossibility to refer to customary law to legitimise espionage under international law (Ziolkowski, supra note 49, p. 438). Back
82 K. Bannelier-Christakis, ‘Military Interventions against ISIL in Iraq, Syria and Libya, and the Legal Basis of Consent’, Vol. 29 L.J.I.L. 2016, pp. 743-775, 767. The maxim can be translated as: ‘He who remains silent, when he ought to have spoken and was able to, is taken to agree’. This principle has been considered by the ICJ in its jurisprudence. See e.g. ICJ, Case concerning the Temple of Preah Vihear (Cambodia v. Thailand) , 15 June 1962, I.C.J. Rep. 1962, pp. 6-36, 23; Land and Maritime Boundary between Cameroon and Nigeria (Cameroon v. Nigeria: Equatorial Guinea intervening) , 10 October 2002, I.C.J. Rep. 2002, pp. 303-602, 485 (Dissenting opinion of Judge Koroma). See also Dr Henry’s extended analysis on the value of acquiescence in the customary norm-shaping process in E. Henry, ‘Alleged Acquiescence of the International Community to Revisionist Claims of International Customary Law (with Special Reference to the Jus Contra Bellum Regime)’, Vol. 18 Melbourne Journal of International Law 2017, pp. 260-297, 266. Back


conduct. States’ silence may in fact be held ‘qualified’, i.e. a manifestation of tacit recognition, 83 hence significant to the definition of a possible customary law rule, although the matter is open to debate. 84 Yet, the use of countermeasures by the victim State would implicitly entail its opinion on the wrongfulness of the conduct undertaken by the spying State. 85 Conversely, the victim State’s uncertainty as to what countermeasures to use against acts of espionage might imply that it considers such conduct indeed legal (or not illegal). 86

According to the International Law Commission, tolerance of a certain practice may count as evidence of opinio juris when:
‘First, […] a reaction to the practice in question would have been called for: this may be the case, for example, where the practice is one that affects — usually unfavourably — the interests or rights of the State failing or refusing to act. Second, […] the State concerned must have had knowledge of the practice (which includes circumstances where, because of the publicity given to the practice, it must be assumed that the State had such knowledge), and that it must have had sufficient time and ability to act’ 87.
Cases concerning States’ reaction to acts of espionage, including those which were made public by Wikileaks or in the Snowden affaire, have been extensively and comprehensively reported by scholars in their writings, 88 such that any further analysis would be of little use from a scholarly point of view. The outcome of their research indicates that States are reluctant to react officially when they find out they have been victims of acts of espionage. 89 When they do react, their official statements, including official protests, do not contain any reference to the legality or illegality of

83 ICJ, Delimitation of the Maritime Boundary in the Gulf of Maine Area (Canada/United States of America) , 12 October 1984, I.C.J. Rep. 1984, pp. 246-352, 305. Acquiescence is considered in art. 45 ARSIWA (supra note 19, p. 121). The way the norm is formulated suggests that acquiescence to an alleged breach of international law operates more like a procedural, rather than a substantive defence, from responsibility claims (A.P. Newcombe and L. Paradell, Law and Practice of Investment Treaties: Standards of Treatment (Alphen aan den Rijn: Kluwer Law International, 2009), p. 525). Back
84 According to the ILC, ‘inaction’ may count as State practice as well, but ‘only deliberate abstention from acting may serve such a role: the State in question needs to be conscious of refraining from acting in a given situation’ (ILC, supra note 78, p. 133). See also J.H. Smith, ‘Keynote Address’, Vol. 28 Michigan J.I.L. 2007, pp. 543-552, 544: ‘[B]ecause espionage is such a fixture of international affairs, it is fair to say that the practice of states recognizes espionage as a legitimate function of the state, and therefore it is legal as a matter of customary international law’. Smith’s opinion is questioned in R. Buchan, ‘Cyber Espionage and International Law’, in N. Tsagourias & R. Buchan (eds), Research Handbook on International Law and Cyberspace (Cheltenham, Edward Elgar 2015), pp. 168-189, 185. According to Bowman, ‘[r]eciprocal tolerance [among States in spying activities] suggests, at minimum, a movement toward customary international law’ (Bowman, supra note 22, p. 328). According to Professor Chesterman, however, Bowman’s assertion on the birth of a customary international norm is ‘probably overstated’ (Chesterman, supra note 21, p. 1097). See also Ziolkowski, supra note 49, p. 442: ‘[T]he consistent State practice of espionage activities and the lack of opinio juris on its illegality do not constitute the practice’s (positive) legality’. Back
85 ARSIWA, supra note 19, p. 129 (Commentary to art 49). Back
86 As the ILC acknowledges in its Draft Conclusions on Identification of Customary International Law: ‘Failure to react over time to a practice may serve as evidence of acceptance as law (opinio juris), provided that States were in a position to react and the circumstances called for some reaction’ (ILC, supra note 78, p. 140 – Conclusion 10). See also Pun, supra note 22, p. 375. Back
87 ILC, supra note 78, p. 142. Back
88 See e.g. K. Kittichaisaree, Public International Law of Cyberspace (Cham, Switzerland: Springer, 2017), p. 255; Lafouasse, supra note 71, p. 121; Chesterman, supra note 21, p. 1083. Back
89 For instance, after having destroyed a US satellite orbiting 500 miles over their country in early 2007, the Chinese authorities did not release any official statement, nor did the US Government: W.J. Broad & D.E. Sanger, ‘Flexing Muscle, China Destroys Satellite in Test’, 9 January 2007, . Back


espionage, 90 with some exceptions though. 91 However, remarkably, the latter are all concentrated in the last few years and almost all of them concern reactions to the US cyber-espionage programme carried out by the NSA and unveiled by Edward Snowden. Here it is worth observing that: a) the NSA programme included capacities that the victim States did not possess and were likely not to possess in the near future; and, b) following their claim on the alleged breach of international law, no countermeasures have been officially taken or reparations asked by the victim States. Based on that, these allegations sound more like a strong disappointment for having no possibility to publicly deny to be disarmed in front of the NSA action, rather than true accusations of its illegality. It is also worth considering that, after the leaks on the NSA spying activity, the US Government has never even apologised for having wiretapped other countries’ heads of State. 92 What is more, one of the victim States, namely Germany, was itself lately suspected to have spied on European citizens and companies at the behest of the NSA, 93 and requested from the US the conclusion of a no-spy agreement. 94 Even the language used in the UN General Assembly Resolution that was approved in the aftermath of the NSA scandal reveals a moderate reaction by the international community, which did not go beyond underlining the concern for the effects of extraterritorial surveillance of communications over the enjoyment of human rights, especially the right to privacy. 95 All the above quoted elements head in the same direction, as they all reveal a good deal of tolerance by the spied States against foreign espionage. Even if one does not accept that a customary rule has already been formed, undeniably there are clear signs that nowadays both State practice and opinio juris are evolving towards the acceptance of the legality of espionage.

If the victim States’ reaction towards other States is therefore rather mild, the same does not apply to suspected spies. 96 On the whole, it might be said that there is a trend to criminalise other States’ spies 97 as if the responsibility for conducting spying activities bore exclusively on them.

90 Ziolkowski, supra note 49, p. 441; P.C.R. Terry, ‘“Absolute Friends”: United States Espionage against Germany and Public International Law’, Vol. 28(2) Revue québécoise de droit international 2015, pp. 173-203, 184. Back
91 The Mexican Ministry of Foreign Affairs called the espionage programme carried out by the NSA ‘unacceptable, illegitimate and contrary to Mexican law and international law’: Der Spiegel, ‘Mexico Slams US Spying on President’, 21 October 2013, . The Brazilian President stated in front of the UN General Assembly that ‘[t]ampering in such a manner in the affairs of other countries is a breach of international law and is an affront of the principles that must guide the relations among them’: quoted in J. Borger, ‘Brazilian president: US surveillance a “breach of international law”’, 24 September 2013, . In 2014, the Government-owned China's Internet Media Research Centre contested that the NSA programme ‘flagrantly breached international laws, seriously infringed upon the human rights and put global cyber-security under threat’: Associated Press in Beijing, ‘China demands halt to “unscrupulous” US cyber-spying’, 27 May 2014, . Back
92 See the US President’s remarks in presenting the Presidential Policy Directive 28, adopted following revelations on the NSA spying programme: ‘Our intelligence agencies will continue to gather information about the intentions of governments - as opposed to ordinary citizens - around the world, in the same way that the intelligence services of every other nation does. We will not apologize simply because our services may be more effective’ (The White House, ‘Remarks by the President on Review of Signals Intelligence’, 17 January 2014, ). Back
93 A. Smale, ‘Germany, Too, Is Accused of Spying on Friends’, 5 May 2015, . Back
94 In the end, the request was reportedly rejected by the US Government: K. Daugirdas & J. Davis Mortenson (eds), ‘Contemporary Practice of the United States Relating to International Law’, Vol. 108 A.J.I.L. 2014, pp. 783-842, 817. Back
95 UNGA, The Right to Privacy in the Digital Age, UN Doc. A/RES/68/167, 18 December 2013. Back
96 See e.g. Deeks, supra note 60, p. 627. Back
97 K.A. Vara, ‘Espionage: A Comparative Analysis’, Vol. 22 ILSA Journal of International & Comparative Law 2015, pp. 61-90, 66-70. See recently T. Winter, K. Dilanian & J. Dienst, ‘Alleged CIA China turncoat Lee may have compromised U.S. spies in Russia too’, 20 January 2018, ; P. Caruso, ‘The Rising Tide of China's Human Intelligence’, 1 March 2018, . Back


V. Balancing Espionage With its Consequences

1. The Right Proportionality Test

Based on the reasoning developed in the previous sections, it may be hypothesized that espionage is legal under international law, both during and outside armed conflicts, especially if one considers that it is exercised in the context of a legitimate worldwide competition among States, as envisioned in the NSS.

Nonetheless, depending on the circumstances of the case, espionage may interfere with a number of other international law obligations of the spying State. 98 In this respect, a possible solution could be that of striking a balance between the aim of espionage and the potentially conflicting obligations, by applying a proportionality test. This approach represents a standard practice in constitutional law and it is common to all areas of public international law, when the legality of the exercise of a State power depends on the achievement of a wider, general public interest. 99 In public law, applying a proportionality principle entails using a three-prong test on: (a) the suitability of a measure that interferes with a right/obligation to achieve its purpose; (b) its necessity in view of that purpose; and (c) the possibility to strike a balance between the relative intensity of the interference and the importance of the aim sought. 100 The latter phase is also called ‘proportionality strictu sensu’ or ‘narrow proportionality’.

Applying this test to espionage, we may assume that its purpose in the era of permanent competition is that of obtaining relevant information for the State’s survival, security and wealth, including those of the social community that lives within its borders. That being said, we may also assume that espionage is both suitable and necessary for this purpose, so that the only condition that remains to be assessed is whether the benefits it generates may prevail over its interference with other State obligations.

However, if we assume that the beneficiaries of espionage are the spying State and its population, we must also consider that those affected by espionage are in the first instance foreign States/entities. In these circumstances, striking a balance in the sense expressed above becomes a tricky move, as those who should benefit (active subjects) and suffer (passive subjects) from the same conduct (espionage) do not belong to the same community and this implies the problem of identifying a higher, common interest to refer to when balancing pros and cons.

An alternative, suitable pattern of reference could be represented by the proportionality test that applies in jus ad bellum. Here – exactly like in the case of external espionage – the entities who are supposed to benefit and suffer from the military action, i.e. the attacking State/population and the target State/population, are diverse, so that a line of reasoning based on a presumed analogy between the legality to use armed force and the legality to carry out espionage activities, may

98 In practice, as Professor Pun observes, the situation at hand can be summarised in a simple question: ‘How is [a] State […] supposed to behave then when the ultimate goal is not prohibited [or better legitimate] under existing international law, but the means can be a violation?’ (Pun, supra note 22, p. 374). Back
99 See A. Stone Sweet & J. Mathews, ‘Proportionality Balancing and Global Constitutionalism’, Vol. 47 Columbia Journal of Transnational Law 2008, pp. 68-149; E. Cannizzaro, Il Principio della Proporzionalità nell'Ordinamento Internazionale (Milan: Giuffré, 2000); N.A.J. Croquet, The Role and Extent of a Proportionality Analysis in the Judicial Assessment of Human Rights Limitations Within International Criminal Proceedings (Leiden, Nijhoff, 2015), p. 24. See in particular the proportionality test applied between conflicting human rights obligations (B. Cali, ‘Balancing Human Rights - Methodological Problems with Weights, Scales and Proportions’, Vol. 29 Human Rights Quarterly 2007, pp. 251-270, at 252) or in the conflict of interests arising out from competing international investment law and international human rights law norms (see e.g. ICSID, SAUR v. Argentina, 6 June 2012, Affaire CIRDI No. ARB/04/4, §§ 330-332 (Décision sur la Compétence et sur la Responsabilité); J. Krommendijk & J. Morijn, ‘”Proportional” by What Measure(s)? Balancing Investor Interests and Human Rights by Way of Applying the Proportionality Principle in Investor-State Arbitration’, in P-M. Dupuy, E-U. Petersmann, & F. Francioni (eds), Human Rights in International Investment Law and Arbitration (Oxford: OUP, 2009), pp. 421-455, 448). Back
100 S. Tsakyrakis, ‘Proportionality: An Assault on Human Rights?’, Vol. 7 International Journal of Constitutional Law 2009, pp. 468-493, 474. Back


possibly apply. The analogy with a type of proportionality test that applies in armed conflicts is reinforced by the assumed end of the peace/war dualism described above, which paves the way to a permanent conflict-type scenario characterising the age of permanent competition. In jus ad bellum, when launching a defensive attack, States are obliged to struck a balance between ‘the need to repel the attack and the harm that defensive military action is likely to result in for other values and interests at stake, such as values of a humanitarian nature’, 101 so that the achievement of the military action’s goal is not disproportionate in respect of ‘what is normally considered the social cost of a defensive reaction’. 102 However making such an assessment is rather difficult, as it often entails comparing values that are not quantifiable. 103 Still, under this rationale, just as – for instance – the use of nuclear weapons is to be balanced against the consequences on the environment produced by the nuclear fall-out, 104 a balance can be struck between the aim of a specific spying activity (i.e. the benefits for the spying State) and the consequences suffered by the target State/entity as a result of such activity. Therefore, much would depend on the particular circumstances of the case and the final assessment may vary according to the obligations that a specific espionage activity interferes with.

2. The Right to Privacy

The international law rules/obligations that espionage may interfere with, range, inter alia, from the principle of sovereignty to the rules on the immunity of diplomatic offices, and the protection of human rights law and beyond. In the case of human rights law, espionage interferes principally, but not solely, 105 with the individuals’ right to privacy. However, this right is not absolute and accepts derogations if they are not arbitrary, provided by law, 106and ‘necessar y […] in the interests of national security, public safety or the economic well-being of the country’. 107 This provision is explicit in allowing a balance of rights and interests, so that a spying activity could possibly – but also rather easily – be said to prevail over the spied individuals’ right to privacy. A necessary precondition is that the spying State has regulated its espionage activities in domestic law. Unsurprisingly, – as we mentioned in Section IV(2) – States have the tendency to do so.

Nonetheless, the balance of interests included in the norms on the right to privacy reflects the paradigm reported in Sub-Section V(1) and used in constitutional law, as the precondition for its application is that the spying State’s right to espionage and the conflicting human rights obligations are both related to the same espace juridique, namely – in practice – to situations in which the spied entity comes under the spying State’s extraterritorial jurisdiction. 108 Indeed, this circumstance is often negated by the spying State, due to the latter’s lack of ‘effective control’, hence jurisdiction, over the targets. 109 By using this line of reasoning, States may in practice conduct external espionage free from any major legal hurdle. 110

101 E. Cannizzaro, ‘Contextualizing Proportionality: Jus ad Bellum and Jus in Bello in the Lebanese War’, Vol. 88 I.R.R.C. 2006, pp. 779-792, 784. Back
102 Id. Back
103 D. Kretzmer, ‘The Inherent Right to Self-Defence and Proportionality in Jus Ad Bellum’, Vol. 24 E.J.I.L. 2013, pp. 235-282, 278. Back
104 ICJ, Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, 8 July 1996, I.C.J. Rep. 1996, p. 242, § 30. Back
105 See e.g. The right to private property in UDHR, art. 17, or Protocol 1 to the ECHR, art. 1. Back
106 ICCPR, art. 17. Back
107 ECHR, art. 8. Back
108 See e.g. ECHR, art. 1 and ICCPR, art. 2. Back
109 Ziolkowski, supra note 49, p. 434. Back
110 For instance, the US position has always been that international human rights law obligations, including the right to privacy, apply only to those who are both within the US territory and subject to the US jurisdiction, so to exclude espionage activities abroad (F. Bignami & G. Resta, ‘Human Rights Extraterritoriality: The Right to Privacy and National Security Surveillance’, in E. Benvenisti & G. Nolte (eds), Community Interests Across International Law (Oxford: OUP, 2018), pp. 357-380). The Foreign Intelligence Surveillance Act (FISA) does not in fact extend to spying activities outside the US (50 U.S.C. § 1801 et seq., Sec. 702(b)). This in the attempt to exclude the justiciability before US courts of conducts carried out by US intelligence officers abroad (Radsan, supra note 49, p. 617). The US is notably not alone in purporting this interpretation. As it was cleverly noted by Marko Milanovic, in condemning Russia for the recent alleged poisoning of a former British spy (and former Russian military officer) and his daughter in the UK, the British government most-likely purposefully avoided to include accusations of the Russian Government failing to comply with its obligations under human rights law. This would have in fact entailed admitting that Russia’s human rights treaty law obligations extend extraterritorially to a killing in the UK (but also – mutatis mutandis – to a targeted killing by a British drone strike in Yemen), that is – exactly like espionage – an activity which does not necessarily imply bringing the target under the killing/spying State’s jurisdiction: M. Milanovic, ‘The Salisbury Attack: Don’t Forget Human Rights’, 15 March 2018, . See on the matter the ‘effective control’ test to establish jurisdiction as developed by the ECtHR in Bankovic – a case which concerned the aerial bombing of the Former Republic of Yugoslavia by NATO forces (ECtHR (GC), Banković and Others v Belgium and Others, Application No. 52207/99, 12 December 2001, Decision as to the admissibility, § 80. Back


Conversely, recent studies, based on a sound legal rationale, confirm the potential applicability of human rights treaty law provisions on the right to privacy to state-run foreign surveillance. 111 If one agrees that human rights law provisions apply extraterritorially to external espionage, then a balance can be struck by analogy under the model elaborated in constitutional law. On the contrary, if one denies the extraterritorial application of human rights law to espionage, still a balance between pros and cons can be struck under the jus ad bellum paradigm reported in Sub-Section V(1). In the latter case too, placing national interests (i.e. the interests of a wider community) before the interests of foreign individuals to their private life would not be difficult in legal terms.

The issue of the interference between States’ foreign surveillance and human rights has been recently brought to the attention of international human rights courts and bodies. Born as a spill over of the Snowden affaire, three cases were brought in 2013-2015 by human rights watchdogs and an investigative journalism organization before the European Court of Human Rights (ECtHR), concerning: the bulk interception of communications by the UK intelligence services; intelligence sharing with foreign governments; and the obtaining of communications data from communications service providers. The cases were jointly decided on 13 September 2018. 112 At the heart of the Court’s decision there was the balance between the right to respect private life and correspondence under Article 8 of the ECHR and the freedom of expression under Article 10 of the ECHR, on the one hand, and the power of States to intercept communications and share them on national security grounds, on the other hand. On the merits, with the exception of the count on intelligence sharing, the UK was condemned for having violated both articles. However, relying on its previous jurisprudence, 113 the Court maintained that ‘the national authorities enjoy a wide margin of appreciation in choosing how best to achieve the legitimate aim of protecting national security’, 114 including the bulk interception of communications, as long as they put in place adequate and effective safeguards against abuses. In balancing pros and cons of secret surveillance measures, the Court seemed to support the idea that – in general – the aim of preserving national and human security always prevails over the obligation to guarantee the individual rights to private life and correspondence and the freedom of expression, as it held: ‘It is clear that bulk interception is a valuable means to achieve the legitimate aims pursued, particularly given the current threat level from both global terrorism and serious crime’. 115

In the Court of Justice of the European Union’s decision on the transfer to the US of personal data gathered through social networks in Europe, the Court asserted that ‘legislation permitting the public authorities to have access on a generalised basis [italics added] to the content of electronic communications must be regarded as compromising the essence of the fundamental right to

111 M. Milanovic, ‘Human Rights Treaties and Foreign Surveillance: Privacy in the Digital Age’, Vol. 56 Harvard International Law Journal 2015, pp. 81-146. Back
112 ECtHR, Big Brother Watch and Others v the United Kingdom, Applications Nos. 58170/13, 62322/14, 24960/15, 13 September 2018, Judgement. Back
113 ECtHR, Weber and Saravia v Germany, Application No. 54934/00, 29 June 2006, Decision as to the Admissibility, § 106. See also ECtHR (GC), Roman Zakharov v Russia, Application No. 47143/06, 4 December 2015, Judgment, § 232; and ECtHR, Irfan Güzel v Turkey, Application No. 35285/08, 7 February 2017, Judgment, § 85. Back
114 Big Brother Watch, supra note 112, § 314. Back
115 Id. , § 386. Back


respect for private life’. 116 One might then wonder what the Court’s opinion would be in cases concerning access to electronic communications ‘on a specific basis’, e.g. when specific electronic communications of interest are intercepted.

In its 2016 resolution on the right to privacy in the digital age, the Third Committee of the UN General Assembly underlined that ‘while concerns about public security may justify the gathering and protection of certain sensitive information [italics added], States must ensure full compliance with their obligations under international human rights law’. 117

Interestingly, one key international human rights body – namely the UN Office of the High Commissioner for Human Rights (OHCHR) – seems to address the matter by applying the ‘jus ad bellum’ proportionality test. Indeed, according to the OHCHR, national security interests are to be balanced against the right to privacy by applying a proportionality test between the degree of interference and the ‘actual benefit’ to be achieved, 118 so that surveillance measures are justified when they are ‘necessary and proportionate’. 119 This entails somewhat an implicit acceptance of a conflict scenario where the collection of information may be regarded as a lawful means of coercion, thus supporting the idea developed in the previous sections on the ‘normalization’ of spying at the sunset of the war/peace dualism.

3. The Principle of Sovereignty

The physical penetration of foreign agents into the territory of a State to conduct espionage activities is generally considered a violation of the principle of sovereignty. 120 But how can espionage that is conducted remotely, for instance using cyber capabilities, be considered? The Tallinn Manual 2.0 offers a somewhat tautological response to such a question, 121 but on the whole it leaves the legality door open to the exfiltration of classified information, even when the consequences for the target State are particularly severe. 122 There are scholars who support this view and exclude any violations of State sovereignty even when the spying State’s agents have to actively remove cyber defences in order to have access to information. 123 Others come to the same conclusion basing their assessment on the cyber environment’s ‘global commons’ nature. 124 Conversely, the opponents of this view observe that ‘the mere fact that a State has intruded into the cyber infrastructure of another State should be considered an exercise of jurisdiction on foreign territory, which always constitutes a violation of the principle of territorial sovereignty’. 125

Whatever view one may choose, if one looks at State practice, it is apparent that those States which possess the technological capabilities to undertake this form of espionage, e.g. the US and the UK, seem to interpret the principle of sovereignty and territorial integrity as not constraining

116 CJEU (GC), Maximillian Schrems v Data Protection Commissioner (Digital Rights Ireland Ltd joining) , Case No. C-362/14, 6 October 2015, § 94. Back
117 UNGA, The Right to Privacy in the Digital Age, UN Doc. A/C.3/71/L.39/Rev.1, 16 November 2016. Back
118 HRC, The Right to Privacy in the Digital Age, UN Doc. A/HRC/27/37, 30 June 2014, § 24:
‘Surveillance on the grounds of national security or for the prevention of terrorism or other crime may be a “legitimate aim” for purposes of an assessment from the viewpoint of article 17 of the Covenant. The degree of interference must, however, be assessed against the necessity of the measure to achieve that aim and the actual benefit it yields towards such a purpose’. Back
119 Id. , § 25. Back
120 Wright, supra note 54, p. 12; Kish & Turns, supra note 44, p. 88. But see a contrario Bowman, supra note 22, p. 328. Back
121 Tallinn Manual 2.0, supra note 19, p. 25: ‘[I]f espionage is carried out by means of cyber operations that are of a nature to breach [the Manual’s rule on the prohibition to violate State sovereignty], said operations qualify as a violation of sovereignty’. Back
122 Id. , p. 171. Back
123 Ziolkowski, supra note 49, p. 459. Back
124 Pun, supra note 22, p. 384. Back
125 W. Heintschel von Heinegg, ‘Territorial Sovereignty and Neutrality in Cyberspace’, Vol. 89 International Legal Studies 2013, pp. 123-156, 129. Back


their intelligence activities abroad. 126 A fortiori, one could then posit that such States believe that they do not infringe other States’ sovereignty when they conduct this kind of activity. In the same direction heads a 2017 Memorandum on cyber operations written by the General Counsel of the US Department of Defence, in which it is mentioned that the principle of sovereignty should not be considered an international law rule; rather, ‘a baseline principle […] undergirding binding norms’, 127 such as the prohibition on the use of force and prohibition of intervention in internal affairs. 128 Along the same lines, in a most recent speech given by the UK Attorney General, the latter affirmed that
‘[s]overeignty is of course fundamental to the international rules-based system. But I am 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’. 129
Clearly, if the principle of sovereignty ceases to be legally binding, cyber espionage against foreign targets does not infringe it.

It may be also observed that the principle of State sovereignty is definitely not absolute. States may well accept limitations to their sovereignty, if they deem that other States would do the same, reaching a common good, e.g. peace and security. 130 Assuming that espionage – by whatever means it is conducted – does indeed violate the sovereignty of the target State but is fundamental to achieve international peace and security, it could nevertheless be argued that, in light of its diffusion and reciprocal exercise, States have implicitly consented to a limitation of their sovereign rights.

The same goal of bypassing the principle of State sovereignty may be achieved under a different and more persuasive view, though. As noted by Kish and Turns, ‘[a]s war prevails over sovereignty, the peacetime prohibition of espionage in national spaces does not apply between belligerent States’. 131 If the peace/war dualism ceases to exist, with the following rise of a permanent low-intensity-conflict-type scenario, the same rationale could easily apply to competing, rather than fully belligerent, States, at least when the status of their confrontation comes near to the conflict side of the international relations’ spectrum.

The International Court of Justice dealt with the issue of the relationship between espionage and national sovereignty in a case related to the theft of documents belonging to the Timorese government by Australian agents, in the context of an arbitration between East Timor and Australia. 132 In its initial application, East Timor claimed that the theft amounted to a breach of sovereignty and the right to confidentiality in the communications with its legal counsels, as the documents had been stolen from one of them. 133 Interestingly, the Australian Attorney-General defended the theft of documents, stating that he had authorised the raid on national security grounds, based on the Australian Security Intelligence Organization Act of 1979. 134 In essence, according to the Australian authorities, any possible right of inviolability over the stolen

126 Deeks, supra note 60, p. 664. Back
127 Quoted in M. N. Schmitt and L. Vihul, ‘Respect for Sovereignty in Cyberspace’, Vol. 95(7) Texas Law Review 2017, . Back
128 Id. Back
129 J. Wright QC MP, Cyber and International Law in the 21st Century (London, Chatham House, 23 May 2018), . Back
130 Bitton, supra note 63, p. 1043. Back
131 Kish & Turns, supra note 44, p. 123. Back
132 ICJ, Questions relating to the Seizure and Detention of Certain Documents and Data (Timor-Leste v. Australia) , Provisional Measures, Order of 3 March 2014, I.C.J. Rep. 2014, pp. 147-162. Back
133 Id. , p. 152, § 24. Back
134 ABC, East Timor Spying Row: Australia Asked to Return Documents Seized in ASIO Raid on Bernard Collaery's Office, 10 December 2013, . Back


documents fails when it is balanced against national security. 135 Notably, international legal scholars interviewed by the media supported the Australian spying activities, arguing that such activities were relevant to both Australia's foreign relations and national economic well-being. 136 Unfortunately, the ICJ did not pronounce on the merits, as the application was dropped following the restitution of documents to the owners. 137 Nonetheless, this confirms that, in case of need, States are ready and willing to balance their national security with the sovereign rights of other States.

4. The Prohibition of Intervention in Internal Affairs

On a different note, it has also been held that espionage tout court represents a form of intervention in the spied State’s internal affairs, irrespective of whether it entails the physical penetration of the spied State’s territory, based on the Nicaragua dictum. 138 However, those who purport the latter position tend to confound espionage with the concept of ‘covert action’, 139 while we deem that the two concepts must be kept distinct. 140 In truth, the concept of ‘intervention’ is characterised essentially by the element of coercion 141 that is lacking in the definition of espionage as reported above. 142 This means that espionage per se may hardly breach the principle of non-intervention.

5. The Immunity of Diplomatic Missions

Diplomatic offices are historically both a target of the receiving State’s intelligence services and the sending State’s outpost to conduct espionage activities. 143 This occurs notwithstanding the existence of the principle of inviolability of diplomatic missions/documents/communications and the diplomatic personnel’s obligation to abide by the receiving State’s laws, respectively. 144 When accredited as members of a foreign diplomatic mission/staff, the sending State’s higher-level spies are even granted de facto, by the receiving State, some kind of protected status under the Vienna Convention on Diplomatic Relations (VCDR). 145 The fact that the receiving States are – at best – unsure about the service that such foreign diplomatic officers truly undertake in their territory is demonstrated by the fact that the first reaction to a public scandal concerning foreign espionage/covert action is always the ‘expulsion’ 146 of a number of diplomats, even if not accused of being directly involved in the scandal in question. 147 This may entail that the receiving States

135 Timor-Leste v. Australia, supra note 132, p. 152, § 25. Back
136 ABC, Would spying on East Timor by the Australian Secret Intelligence Service be Illegal? , 11 December 2013, . Back
137 The Court, however, found that the Timorese claim was ‘plausible’ (Timor-Leste v. Australia, supra note 132, p. 153, § 28), giving the idea that the aforesaid balance could have potentially been solved in favour of the applicant, perhaps under ethical, rather than legal, reasons (R.J. Bettauer, ‘Questions Relating to the Seizure and Detention of Certain Documents and Data’, Vol. 108 A.J.I.L. 2014, pp. 763-769, 768). Back
138 Nicaragua, supra note 19, § 202. J. Beim, ‘Enforcing a Prohibition on International Espionage’, Vol. 18 Chicago Journal of International Law 2018, pp. 647-672, 654. Back
139 Fleck, supra note 16, pp. 690-694. Back
140 See supra note 39. Back
141 Nicaragua, supra note 19, § 205. Back
142 See, supra Section III. Back
143 Deeks, supra note 60, p. 642. Back
144 Convention on the Diplomatic Relations (VCDR), Vienna, 18 April 1961, (1965) 500 U.N.T.S. 95, arts 22, 24, 27 and 41. Back
145 Id. , art. 37. Back
146 Rectius, the officers concerned are declared personae non gratae under VCDR, art 9. Back
147 For instance, following the alleged poisoning by the Russian intelligence services of a former British spy (who had been previously a Russian military officer) and his daughter in the UK in March 2018, dozens of Russian diplomats were declared personae non gratae in more than 20 countries, including 18 European Union States, the US and Canada (A. Dewan, M. Veselinovic & C. Jordan, ‘These Are All the Countries that Are Expelling Russian Diplomats’, 28 March 2018, ). Back


allow, to a certain extent, the possible presence of foreign spies in their territory, insofar the sending States are willing to do the same with them. Granting diplomatic status to foreign spies could amount to a possible implicit recognition of their role.

In the Tehran case, the ICJ put the obligation to respect the inviolability of diplomatic missions in relation with the principle of reciprocity. 148 However, if reciprocity is the founding element of the rule on inviolability, the acceptance by States of reciprocal espionage could be said to have tempered this rule, so that its absolute character can be now questioned.

If instead one accepts that diplomatic offices and their communications are inviolable, a balance in the sense seen above can still be struck. More specifically, here one could posit a balance between espionage activities conducted from and against diplomatic offices. As Kish and Turns already noted in 1995: ‘[S]atellite broadcasting has facilitated diplomatic communications by the sending State, while the electronic surveillance of diplomatic communications has protected the national security of the receiving State. These developments indicate new directions for the revision of the international law of diplomatic communication’. 149

The issue of the immunity of diplomatic offices – or better the immunity of diplomatic documents and communications – has come to the attention of the public in a recent case decided by the UK Supreme Court. In Bancoult 3 150 the UK Supreme Court was called to decide on the admissibility before British courts of a confidential document originated by the US Embassy in London which had been released to the public by Wikileaks and then submitted to the lower courts by the applicants. In upholding the principle of inviolability of diplomatic documents, the Court limited the protection offered by the VCDR to the existence of two conditions: (1) the document must constitute or remain part of the mission archive; and (2) its contents must not have been publicly disseminated. 151 Diplomatic documents are to be considered part of the mission archive until ‘they are under the control of the mission’s personnel, as opposed to other agents of the sending state’. 152 This interpretation, however, ends up restricting the inviolability of these documents and seems contradictory to Article 24 of the VCDR, which affirms that ‘[t]he archives and documents of the mission shall be inviolable at any time and wherever they may be [italics added]’. 153 See, for instance, a situation where a sending State’s officer – e.g. a fonctionnaire of the Ministry of Foreign Affairs, who does not belong to a diplomatic mission – is given a confidential document while on visit to the embassy. Applying the rationale of Bancoult 3, the inviolability of the document concerned would end once the fonctionnaire leaves the embassy building.

VI. Conclusion

The analysis contained in the previous sections shows that there are good reasons to support the legality under international law of State-run espionage, conducted outside open conflict situations. The legality of espionage may be justified by appealing to the end of the war/peace dualism in international relations, as inferred from the new US NSS, or by having regard to the practical identity in the way the legal regimes of espionage in both peacetime and wartime are construed de facto. In addition, the legality of State-run espionage may be substantiated by

148 ‘…[T]here is no more fundamental prerequisite for the conduct of relations between States than the inviolability of diplomatic envoys and embassies, so that throughout history nations of all creeds and cultures have observed reciprocal obligations for that purpose…’: ICJ, United States Diplomatic and Consular Staff in Tehran case (United States of America v. Iran) , Request for the indication of provisional measures, Order of 15 December 1979, p. 19, § 38, . Back
149 Kish & Turns, supra note 44, p. 69. Back
150 UK Supreme Court, R (on the application of Bancoult No 3) v. Secretary of State for Foreign and Commonwealth Affairs, 8 February 2018, [2018] UKSC 3, . Back
151 Id. , § 20. Back
152 Id. , § 68. Back
153 Indeed, critics of the Bancoult 3 decision argue that ‘interpreting inviolability to mean that leaked documents are inadmissible in the courts of VCDR State parties would be consistent with the object and purpose of the VCDR’ (P. Grané Labat & N. Burke, ‘The Protection of Diplomatic Correspondence in the Digital Age: Time to Revise the Vienna Convention?’, P. Behrens (ed), Diplomatic Law in a New Millennium (Oxford: OUP, 2017), pp. 204-230, 223). Back


resorting to customary international law. Since espionage interferes with other international legal obligations for the spying State, a viable option to ensure its legality is that of striking a balance between the spying activity’s aims and the consequences for the target State/entity, under the rationale applied in the proportionality test of both jus ad bellum and – to a more limited extent – constitutional law. In particular, the proportionality test applied in constitutional law may be used by analogy in cases of extraterritorial application of human rights treaty norms. The analysis of the relevant international jurisprudence, documents and official declarations of States and human rights bodies confirms the viability of this approach and demonstrates how – in practice – States may easily develop arguments in support of the legality of their espionage activities.

A logical consequence of positing the legality of espionage would be that of rejecting the growing trend towards criminalization of spies. Affording some kind of protected status to spies would push States to acknowledge their activities in case of capture.

Possibly, accepting the legality of espionage would in turn produce the unexpected effect of making the reality of current international relations more transparent and less hypocritical – in a way, more democratic and peaceful. In fact, it would depict espionage for what it has always been, i.e. a standard practice of States in support of their foreign policy in the context of an international scenario which is increasingly competitive (‘the age of permanent competition’). In essence, legitimizing espionage is the necessary corollary of legitimizing international competition. Refusing to address this parallelism in legal terms, by simply arguing that espionage in an ‘extra-legal’ phenomenon, means rendering international law unfit to regulate international relations.

It goes without saying that this legitimization of espionage would not extend to covert actions or any other form of intervention in the internal affairs of other States.

On the whole, for international lawyers leaving the safe heavens of traditional law institutions and admitting the legality of phenomena like espionage requires a good deal of courage. But this is the age of courage. As Rosa Brooks, law professor at Georgetown University and former counsellor to the US Under Secretary of Defense for Policy, wrote in 2016:
‘Today, we’re coming again to one of history’s crossroads. [...] We created the categories we use, and if they’re no longer serving the purpose we want them to serve, we can change them. To do that, we’ll have to first abandon the effort to draw increasingly arbitrary lines between “peacetime” and “wartime,” and accept that some level of conflict will always be with us – but we don’t have to let it distort our values. [...] Perhaps we can develop institutions and norms capable of protecting human rights and the rule of law not just in peacetime, but in all times’. 154

154 R. Brooks, How Everything Became War and the Military Became Everything: Tales from the Pentagon (New York, Simon & Schuster, 2016), pp. 35-36. Back