The Yale Law Journal

April 2016

The State’s Right to Property Under International Law

Peter Tzeng


On December 3, 2013, agents of the Australian Secret Intelligence Service seized privileged documents belonging to Timor-Leste on the premises of one of Timor-Leste’s legal advisers in Australia.1 The documents concerned an ongoing arbitration between the two states over Australian espionage.2 Two weeks later, Timor-Leste sued Australia before the International Court of Justice (ICJ) for violating its property rights under international law.3 The claim seemed flawless: there was no dispute that Australia had taken the documents.4 Nevertheless, Australia had a response: the taking was lawful because states do not have a general right to property under international law.5

As absurd as it may sound, Australia is correct. But two points of clarification are in order. First, there is no question that individuals have a general right to property under domestic law.6 Australia was merely asserting that states do not have such a right under international law.7 Second, Australia was not arguing that taking another state’s property is always lawful under international law; rather, it merely asserted that a taking can be lawful. In particular, Australia claimed that the state has rights to certain types of property, but not all types of property. Yet even with these qualifications, the thesis still sounds absurd. How can states not have a general right to property under international law?

This Comment explains this unintuitive fact. Surprisingly, very little scholarly work discusses the state’s right to property under international law,8 which formed the basis of Timor-Leste’s original claim9 and received significant attention during oral arguments.10 Most of the secondary literature on Timor-Leste v. Australia has focused on the underlying arbitration rather than the ICJ litigation,11 and commentary on the ICJ case has for the most part focused on the privileged nature of the documents rather than the state’s right to property.12 And unfortunately, the ICJ will not have the opportunity to address the issue in this particular case, as Timor-Leste withdrew its claim in June 2015.13

This Comment makes both a descriptive and a normative argument. Part I argues that as a descriptive matter, states have a general right to territory but an incomplete right to property under international law. Part II makes the normative argument that the international community, which has primarily focused on establishing rights to certain types of property, should now focus on developing the state’s general right to all types of property. Part III offers a short discussion on how that right could emerge.

I. the state’s rights to territory and property

The state has rights to territory and property. The state’s territory is the physical space over which the state exercises sovereignty.14 The state’s property is the set of tangible and intangible objects over which the state exercises ownership,15 such as embassies, buildings, vehicles, and documents.

For the purposes of this Comment, a right is “general” if any interference with it gives rise to a cause of action, whereas a right is “incomplete” if only certain interferences with it give rise to a cause of action. As explained below, the current state of international law is such that the state has a general right to territory,16 but an incomplete right to property.17

A. The State’s General Right to Territory

The state has a general right to territory because any interference with a state’s territory gives rise to a cause of action under international law, either under the principle of state sovereignty or under the prohibition on territorial conquest.

Although taken for granted today, the principle of state sovereignty was not always a norm of international law. As late as the seventeenth century, sovereigns coexisted without well-defined boundaries.18 As a result, they engaged in frequent warfare, culminating in the Peace of Westphalia of 1648,19 which established, inter alia, the principle of state sovereignty: states were prohibited from interfering with another state’s territory.20

Although this prohibition was a significant accomplishment, there was one important exception: states could still lawfully acquire territory from other states through military conquest.21 Consequently, for centuries following the Peace of Westphalia, states continued to engage in warfare to expand their territory.22 It was only after the Kellogg-Briand Pact of 192823 and the U.N. Charter of 194524 that the prohibition on territorial conquest became a respected norm of international law.25 From then on, any interference with a state’s territory constituted a prima facie breach of international law, establishing the state’s general right to territory in the international legal order.26

B. The State’s Incomplete Right to Property

Unlike the state’s right to territory, the state’s right to property is incomplete. Although the Immunities Convention of 200427—which has not yet entered into force28—appears to codify a general right to property, the Convention would apply only to “the immunity of a State and its property from the jurisdiction of the courts of another State.”29 Indeed, its purpose from the very beginning was only to codify the rules of foreign sovereign immunity applicable in national courts; it was never intended to prohibit interference with state property in the international legal order.30

The absence of a general right to property is understandable as a historical matter. Traditionally, states kept all their property within their own territory, such that the general prohibition on interfering with another state’s territory provided sufficient protection for states’ property. But over time, states have needed to locate more and more of their property extraterritorially. In response, international law has evolved to provide protection—often in the form of immunities—for this property. This protection, however, has developed in a piecemeal fashion, creating rights to specific types of property instead of establishing a general right to property.

The first type of protected extraterritorial property is diplomatic property. Originating from the practice of Italian sovereign city-states, diplomatic premises began enjoying immunity in the sixteenth century.31 Today, their immunity has been enshrined in the Vienna Convention on Diplomatic Relations of 1961 (VCDR), which extends immunities to other diplomatic property as well, such as the diplomatic mission’s means of transport, archives, documents, correspondence, and diplomatic bag.32 The Vienna Convention on Consular Relations of 1963 (VCCR) extends similar protections to consular premises and property,33 as does the Convention on Special Missions of 1969 for the premises and property of special missions.34 In the landmark Tehran Hostages case of 1980, the ICJ held the relevant provisions of the VCDR and VCCR to be general international law.35

The second type of protected extraterritorial property is extraterritorial vehicles, including ships, aircraft, and spacecraft. State ships employed for noncommercial purposes have historically enjoyed immunity based on the legal fiction that they form part of their flag state’s territory;36 their immunity is now enshrined in the Unification Convention of 1926,37 the High Seas Convention of 1958,38 and the U.N. Convention on the Law of the Sea of 1982 (UNCLOS).39 Under UNCLOS, state aircraft likewise enjoy the freedom of overflight in the high seas and the exclusive economic zone,40 and under the Paris Convention of 1919, military aircraft enjoy certain immunities in the territory of other states.41 State spacecraft are also accorded a certain degree of immunity under the Outer Space Treaty of 1967.42

Therefore, as a matter of lex lata,43 any interference with a state’s diplomatic property or extraterritorial vehicles gives rise to a cause of action under international law. But where a state interferes with any other type of property belonging to another state, often no such cause of action arises. Indeed, the very existence of treaties specifically protecting diplomatic property and extraterritorial vehicles supports the contention that a general right to property does not exist. After all, if there had been a general right to property, then states would not have had to provide for specific protections in the aforementioned treaties in the first place.

II. the need for a general right to property

If the only types of state property at risk of interference were diplomatic property and extraterritorial vehicles, then there would be no need for a general right to property. However, each year more and more types of state property—both within and outside of state territory—find themselves at risk.

Consider three examples. The first is computer networks: states are increasingly launching cyberattacks on other states’ computer networks, as seen in Estonia,44 Georgia,45 Iran,46 Israel,47 and the United States.48 Second, communication systems: states are increasingly conducting espionage by bugging other states’ communication systems, as evidenced by Brazil,49 Germany,50 Timor-Leste v. Australia,51 and most recently Croatia v. Slovenia.52 Third, privileged documents: documents concerning pending litigations and arbitrations have increasingly been targeted, as was the case in Kazakhstan,53 Philippines v. China,54 and Timor-Leste v. Australia.55 The list of types of state property at risk goes on.

There are two ways to solve this problem. First, there is the piecemeal approach, whereby the state’s right to property develops incrementally by type of property. This has been the prevailing approach for decades, and as a result, today the state has an incomplete right to property (i.e., rights to only certain types of its property).56 The second approach is the holistic approach, whereby the state’s right to property develops as a general matter, such that the default is that all of a state’s property is protected under international law. Under this approach, states would have a general right to property (i.e., rights to all types of its property).

Today, the piecemeal approach continues to prevail. To protect state computer networks, commentators have proposed57 and states have concluded58 cybersecurity treaties. To protect state communication systems, some commentators have similarly pushed for an anti-espionage treaty.59 And to protect privileged state documents, the ICJ declared in its provisional-measures order in Timor-Leste v. Australia that states plausibly have the right to exclude other states from accessing their privileged documents.60

The piecemeal approach undeniably has its benefits: in particular, it allows states to develop regimes of protection customized to each type of property. Nevertheless, there are three reasons why the holistic approach is necessary to supplement the piecemeal approach.

First, the piecemeal approach is reactive, whereas the holistic approach is proactive. Under the piecemeal approach, the state’s right to a certain type of property almost always develops only after interferences with that type of property begin to occur, often due to an innovation in technology. The subsequent process of development takes time: for example, a comprehensive cybersecurity treaty and an anti-espionage treaty have been in the works for decades, allowing states to interfere with state computer networks and communication systems with impunity in the interim.61 Under the holistic approach, on the other hand, states would have a default right to all of their property, even against unprecedented interferences with a specific type of property.

Second, the piecemeal approach places the burden of proof on the victim state, whereas the holistic approach places the burden on the perpetrator state. Under the piecemeal approach, even when one state unquestionably interferes with another state’s property, the victim state must prove that it had a right to that property under international law. For example, in Timor-Leste v. Australia, Timor-Leste carried the burden of proving that it had a right to the confidentiality of its privileged documents, causing years of litigation over what should have been a simple issue.62 Under the holistic approach, the presumption would be reversed, such that the victim state could always invoke its general right to property and the perpetrator state would have the burden of raising an affirmative defense.

Third, the piecemeal approach makes it difficult to articulate a right to previously unrecognized types of property in the court of public opinion, whereas the holistic approach would facilitate such articulation. Under the piecemeal approach, this “articulation difficulty” could lead to impunity for the perpetrator. For example, after the National Security Agency (NSA) tapped Chancellor Angela Merkel’s and President Rousseff’s phone conversations, the German and Brazilian governments had trouble pointing to a specific rule of international law that the United States had violated.63 Ultimately, many commentators conceded that the NSA’s activities did not violate international law at all.64 More dangerously, this “articulation difficulty” may also lead to the distortion of other rules of international law. For example, in light of recent Chinese cyberattacks against American entities,65 U.S. lawyers and academics have been scrambling to find the legal grounds for declaring such action unlawful under international law. Compelled by a sense that significant cyberattacks must somehow violate international law, commentators have developed theories about when a cyberattack amounts to a breach of the prohibition on the use of force under Article 2(4) of the U.N. Charter,66 arguably leading to overly expansive interpretations of Article 2(4).67 The holistic approach, however, would make clear that the fundamental reason why these acts are wrongful is that they are interferences with another state’s property; there should be no need to invoke the laws on the use of force to declare a cyberattack unlawful. Unfortunately, however, the absence of the general right to property under current international law deprives states and commentators of the necessary language to articulate this rationale. For this reason, along with the two previously mentioned, this Comment proposes that the international community take a holistic approach to the problem by working toward a general right to property.68

Skeptics may be concerned that a general right to property goes too far. As Australia argued during the hearings on provisional measures, a general right to property “would allow a State adventitiously to expand its sovereignty into the territory of other States.”69 Nevertheless, history reveals that states are willing to sacrifice aspects of their sovereignty for the equal protection of property rights. After all, states came together to protect diplomatic property and extraterritorial vehicles,70 and states have also come together to protect computer networks.71 The one exception may be espionage: state support for an anti-espionage treaty is relatively weak, and commentators have argued that bugging the communication systems of other states is not necessarily a violation of international law.72 Nevertheless, the general right to property would merely be a default: if espionage is lawful under international law, it would remain lawful. The major difference under a general-right regime would be that the state conducting the espionage would bear the burden of showing its legality.

III. toward a general right to property

The piecemeal and holistic approaches are not mutually exclusive; they should work in tandem. As discussed earlier, commentators and states have already dedicated considerable thought, time, and energy to developing piecemeal solutions to today’s most pressing problems.73 Indeed, efforts to conclude cybersecurity and anti-espionage treaties are commendable. Nevertheless, the predominant concerns of today will be different from those of tomorrow. In the long term, we need a more sustainable solution: a general right to property.

This general right could emerge in one of three ways: by treaty, by custom, or by general principle of law.74 A Convention on the State’s Right to Property sounds appealing, but the political obstacles would likely be insurmountable. States are already having trouble concluding treaties to effectively protect computer networks and communication systems; concluding a treaty to protect all types of property, a fortiori, would be even more difficult. Similarly, the development of a customary general right to property is appealing,75 but it would be difficult to prove the existence of the requisite state practice and opinio juris.76

The most feasible option, then, is the development of a general principle. Unlike treaties and custom, which derive from the acts of states in the international legal order, general principles develop from analogies with the law of domestic legal orders.77 A very strong case may be made that the general right to property similarly constitutes a general principle of law: ninety-five percent of the 193 Member States of the United Nations guarantee a general right to property in their domestic law.78 Although this right only applies to individuals in domestic legal orders, the right may be transposed to the international legal order as a general principle of law to apply to states as well. Applying this right to states is, moreover, supported by the principle of the sovereign equality of states enshrined in Article 2(1) of the U.N. Charter.79

Furthermore, it should be remembered that the Advisory Committee of Jurists80 included general principles of law as a source of international law for the very purpose of avoiding situations of non liquet, where there is no law to apply because the issue at hand is sufficiently novel or unprecedented.81 It therefore seems particularly appropriate to invoke general principles to establish rights over previously unrecognized types of property.


For the aforementioned reasons, this Comment argues that international courts and tribunals should take the initiative of recognizing the state’s general right to property as a general principle of law. The ICJ had the opportunity to do so in Timor-Leste v. Australia, but it instead ordered provisional measures on the far narrower ground of legal privilege.82 But because questions surrounding the state’s right to property are bound to arise in many more cases to come, the next international court or tribunal should not miss the opportunity to assert the state’s general right to property as a general principle of law.