(p. 447) 20 Sovereignty and Equality of States
1. The Concept of Sovereignty1
The sovereignty of states represents the basic constitutional doctrine of the law of nations, which governs a community consisting primarily of states having, in principle, a uniform legal personality.2 If international law exists, then the dynamics of state sovereignty can be expressed in terms of law. If states (and only states) are conceived of as sovereign, then in this respect at least they are equal, and their sovereignty is in a major aspect a relation to other states (and to organizations of states) defined by law.
The corollaries of the sovereignty and equality of states are: (a) a jurisdiction, prima facie exclusive, over a territory and the permanent population living there; (b) a duty of non-intervention in the area of exclusive jurisdiction of other states; and (c) the ultimate dependence upon consent of obligations arising whether from customary law or from treaties. The last of these has certain special applications: in principle the jurisdiction of international tribunals depends on the consent of the parties; membership of international organizations is not obligatory; and the powers of the organs of such organizations to determine their own competence, to take decisions by majority vote, and to enforce decisions depend ultimately on the consent of member states.3
The manner in which the law expresses the content of sovereignty varies, and much of the law could be expressed in terms of the co-existence and conflict of sovereignties. Yet another perspective is provided by the notion of sovereignty as discretionaryReferences(p. 448) power within areas delimited by the law. Thus states alone can confer nationality for purposes of municipal law, delimit the territorial sea, and decide on the necessity for action in self-defence. Yet in all these cases the exercise of the power is conditioned by international law, and compliance with those conditions is not a matter for the acting state alone.
(A) The Competence of States
The term ‘sovereignty’ is variously used to describe the legal competence which states have in general, to refer to a particular function of this competence, or to provide a rationale for a particular exercise of this competence. The word itself has a lengthy and troubled history, and is susceptible to multiple meanings and justifications.4 In its most common modern usage, however, the term is rather descriptive in character, referring in a ‘catch-all’ sense to the collection of rights held by a state, first in its capacity as the entity entitled to exercise control over its territory and second in its capacity to act on the international plane, representing that territory and its people.5 Sovereignty is not to be equated with any specific substantive right, still less is it a precondition to state-hood.6 Thus jurisdiction, including legislative competence over national territory, may be referred to by the terms ‘sovereignty’ or ‘sovereign rights’. Sovereignty may refer to the title to territory or to the rights accruing from the exercise of title. The correlative duty of respect for territorial sovereignty,7 and the privileges in respect of territorial jurisdiction referred to as sovereign (or state) immunity, are described after the same fashion. In general ‘sovereignty’ characterizes powers and privileges resting on customary law which are independent of the particular consent of another state.
(B) Sovereignty as Equality
A corollary of their independence is the equality of states,8 historically expressed by the maxim par in parem non habet imperium.9 In international law, the maxim isReferences(p. 449) frequently invoked as a basis for state immunity, at the core of which (in its restricted modern application) is the concept of equality between sovereigns.10 But equality has further implications: it refers to the juridical conceptualization of the division of power between states. Obviously, the allocation of power and the capacity to project it in reality are different things, which suggests that while all states are equal, some are more equal than others.11
But nonetheless formal equality remains and has meaning. When, by legislation or executive decree, a state delimits a fishing zone or the territorial sea, the manner and provenance of the exercise of such power is in the first place a matter for the state. But when it is comes to enforcing the limit vis-à-vis other states, the issue is placed on the international plane. Similarly, the conferral or withdrawal of nationality may lead to a collision of interest between two states as to the right to exercise diplomatic protection. One might conclude that the criterion depends on a distinction between internal competence—no outside authority can annul or prevent the internally valid act of state power—and international responsibility for the consequences of the wrongful exercise of that competence. This distinction certainly has wide application, but it is not absolute in character. Thus, in particular contexts, international law may place restrictions on the ‘internal’ territorial competence of states as a consequence of treaty obligations, for example, forbidding legislation which discriminates against certain groups among the population. In the case of various territorial privileges, created either by general or local custom or by treaty, other states are permitted to exercise governmental functions, that is, perform sovereign acts, within the territorial domain.
(A) Sovereignty and the Application of Rules12
(i) The performance of obligations arising from treaties
One of the central canons of the customary international law of treaties is the rule pacta sunt servanda, that is, the notion that states must comply with their obligations (p. 450) in good faith.13 No case has yet arisen in which an international court or tribunal repudiated the rule or challenged its validity. From a certain point of view, the rule is axiomatic and self-evident.14 From another, it is in tension with the concept of sovereignty, in that the obligation to perform (and to be held to account for non-performance) appears to restrain a state’s ability to exercise its sovereignty.
In the Wimbledon the Permanent Court firmly rejected the argument that a treaty provision could not deprive a state of the sovereign right to apply the law of neutrality to vessels passing through the Kiel Canal. The SSWimbledonwas a British-owned steamship time-chartered to a French company. On board was a cargo of Italian munitions destined for the Polish naval base at Danzig. Poland was at war with Russia, a conflict in respect of which Germany had pledged neutrality. For fear that German neutrality would be breached if the ship were allowed passage, the Wimbledon was detained and eventually forced to find its way to Danzig through the Denmark Strait, with consequent delays. Britain, France, Italy, and Japan (but not Poland) claimed reparation, asserting that Germany’s refusal to grant passage to the Wimbledon was contrary to Article 308 of the Treaty of Versailles,15 requiring Germany to allow passage through the Kiel Canal to all vessels of nations with which it was not at war.
The Court held that the idea that the treaty restrained Germany’s sovereign right to impose the law of neutrality on the Kiel Canal was fallacious. The treaty itself was an expression of conduct to which the state consented to be bound. Rather than removing the right to apply the law of neutrality to the Kiel Canal, it created an obligation to exercise that right in a certain way, with the capacity to enter into an agreement giving rise to an internationally binding obligation being itself an attribute of sovereignty.16
(ii) Interpretation of treaties
On occasion the International Court has referred to sovereign rights as a basis for a restrictive interpretation of treaty obligations.17 But under the unitary theory ofReferences(p. 451) interpretation set out in VCLT Article 31 and customary international law, everything depends on the context, the intention of the parties, and the relevance of other, countervailing, principles such as that of effectiveness. In certain contexts, this application of other canons of interpretation has led to a complete reversal of the restrictive approach, particularly in circumstances where a dispute concerns a state and a private party.18 Investor-state arbitration tribunals are particularly forward in this respect, often holding that international investment agreements be interpreted either neutrally19 or for the benefit of the private investor.20
Many areas of international law are uncertain or contain principles which do not admit of easy application to concrete issues. Thus much could turn on the answer to the question whether there is a presumption in favour of sovereignty. In another form the issue is whether, in case of doubt as to the mode of application of rules or in case of an absence of rules, the presumption is that states have legal competence or not. In the Lotus the Court decided the issue of jurisdiction on the basis that ‘restrictions upon the independence of States cannot be presumed’.21 But yet again there is no general rule, and in judicial practice issues are approached empirically. Indeed, a general presumption of either kind would lead to inconvenience or abuse. The context of a problem will determine the incidence of the burdens of proof of a given issue: whether that produces a burden of proving a restriction on sovereignty will vary. The ‘jurisdictional geography’ of the problem may provide useful indications: more than one sovereignty may be involved. Thus in Asylum the Court stressed the fact that diplomatic asylum involves a derogation from sovereignty as represented by the normally exclusive jurisdiction of the territorial state.22
(B) Sovereignty and International Organizations23
The institutional aspects of organizations of states result in an actual, as opposed to a formal, qualification of the principle of sovereign equality. In an organization subjectReferences(p. 452) to majority or weighted voting, organs may be permitted to take decisions, and even to make binding rules, without the express consent of all member states. But on joining the organization each member consented in advance to the institutional aspects, and thus in a formal way the principle that obligations can only arise from the consent of states and the principle of sovereign equality are satisfied.
On the other hand, international organizations can evolve and may assume roles very different to that initially contemplated. In the case of the UN the organs have interpreted the Charter in accordance with the principles of effectiveness and implied powers at the expense, it may seem, of Article 2(1) and (7).24 In Certain Expenses, the Court held that in the absence of any particular procedure to determine the validity of the acts of the UN’s institutions, each of them must determine its own jurisdiction.25 Some 40 years later, this position arguably enabled the Security Council to pass several ‘legislative’ resolutions, using its Chapter VII powers.26 These resolutions require states to enact particular domestic laws, thereby supplanting the recommendatory role of the General Assembly, the treaty-making process and the principle of consent.27 True, the Security Council has always had the power to bind UN members to the point of overriding other treaty obligations,28 but legislative resolutions require members to respond to a general phenomenon (the financing of terrorism, the transport of nuclear weapons) rather than a specific situation involving a particular country or region. That is at odds with the original conception of the Security Council as a force for the maintenance of world peace, not the alteration of world order.29
If an organization encroaches on the domestic jurisdiction of members to a substantial degree the structure may approximate to a federation. Given the modern conception of the relationship between states and international organizations, such a position seems inherently unlikely, and in any event, the consent-based conception of this relationship precludes the argument that state sovereignty is under threat from some form of overarching ‘world government’. Pending an (unlikely) revolution, ‘world government’ is an essentially decentralized enterprise, something international law provides because states have accepted it: it is the government we have when we are not having a government.