I. INTRODUCTION
In recent years, courts in Canada,Footnote 1 the United Kingdom (UK),Footnote 2 South AfricaFootnote 3 and the United States (US)Footnote 4 have been confronted with immunity claims by entities that would not ordinarily be entitled to State immunity—private individuals, companies and State officials of the forum State—on the grounds that a decision by the court might ‘affect’ States not parties to the proceedings. In the UK, this issue came to the fore in Belhaj v Straw, where British government officials argued that English courts were precluded from reviewing allegations of their involvement in the unlawful detention and mistreatment of foreign nationals by US and other States’ officials on the grounds that such an enquiry would ‘implead the foreign states’.Footnote 5
Although courts have consistently rejected these immunity claims, the topic remains shrouded in confusion. To varying degrees, all courts seem to have accepted the defendants’ premise that there may be an obligation to grant immunity in cases where the defendant is not the State. Similarly, some scholars maintain that the principle of sovereign equality of States, which underpins immunity (par in parem non habet imperium Footnote 6), precludes domestic courts from reviewing the legality of foreign States’ sovereign acts, irrespective of the defendant's status.Footnote 7 The debate is rife with uncertainty, further complicated by recurring references to legal doctrines of uncertain scope such as ‘indirect impleading’ and ‘act of State’,Footnote 8 or doctrines typically associated with the competence of international courts like the Monetary Gold doctrine.Footnote 9
This confusion may have significant consequences, potentially depriving claimants of judicial remedies in proceedings where determining the activities of third-party States is necessary, or making domestic prosecution of crimes such as aggression—which requires a judicial determination of a third-party State's wrongful actFootnote 10—impossible.Footnote 11 These concerns become even more pressing in the context of ongoing discussions on establishing a special court to prosecute Russia's aggression against Ukraine.Footnote 12
In these scenarios, it is crucial to avoid the ‘Midas effect’, where—much like the mythical Greek king who transformed everything he touched into gold—mere allegations of contact with foreign sovereigns would allow individuals and entities not ordinarily entitled to immunity to evade domestic court jurisdiction. As this article demonstrates, this prospect is the result of a misapprehension of the nature and content of State immunity as evidenced by the practice of domestic courts, and of the relationship between State immunity and other doctrines that must be kept separate from immunity.
This article is structured as follows. Section II examines competing State immunity theories, revealing that despite some support for subject-matter immunity, the preferable view is based on the defendant's status. It further demonstrates that cases involving ‘indirect impleading’ do not undermine the status-based nature of State immunity. Section III argues that characterizing State immunity as a subject-matter rule blurs the distinction between immunity and other doctrines that are either inapplicable to domestic courts or not grounded in international law. Section IV concludes by emphasizing the importance of preserving State immunity within established boundaries to maintain a balance among competing interests. By doing so, the article fosters a more sophisticated and informed discussion, ensuring that justice is not jeopardized by baseless immunity claims.
II. STATE IMMUNITY AS A STATUS-BASED RULE AND THE NOTION OF ‘INDIRECT IMPLEADING’
State immunity, a corollary of the principle of sovereign equality of States,Footnote 13 is often deemed to prevent one sovereign State from ruling or exercising power over another.Footnote 14 In fact, it is more accurate to say that the application of State immunity requires balancing the conflicting sovereignties of the forum State and the foreign State.Footnote 15 Historically, States have adopted at least two models of State immunity to address this need.Footnote 16
The absolute model generally prohibits domestic courts from exercising jurisdiction over foreign States without their consent. In contrast, the restrictive model—now prevalent—exempts foreign States from domestic court jurisdiction only for sovereign acts, not for private or commercial activities. This shift has been justified on the grounds of justice and accountability, especially when States engage in transactions similar to those of private individuals.Footnote 17 However, this explanation falls short of a comprehensive theoretical foundation,Footnote 18 leading to difficulties in identifying the beneficiaries of State immunity. A critical question is whether immunity pertains primarily to the ‘person’ of the State or extends in general to its sovereign activities.
Advocates of a subject-matter approach to State immunity argue that the key element is the exercise of jurisdiction over foreign sovereign activities rather than over foreign sovereign defendants.Footnote 19 Yet, if taken to the extreme, this view would lead to paradoxical results: the restrictive model would have narrowed the scope of immunity to private law acts while expanding the number of potential beneficiaries due to the irrelevance of the defendant's status.
Hence, most authorities agree that the restrictive model, while incorporating elements of subject-matter immunity, remains based on the defendant's status.Footnote 20 To ascertain whether this aligns with the structure of State immunity under customary international law, one must consider State practice and opinio juris,Footnote 21 particularly focusing on national court judgments addressing immunity questions.Footnote 22
The United Nations Convention on Jurisdictional Immunities of States and Their Property (UNCSI), though not in force,Footnote 23 is a useful starting point for this enquiry.Footnote 24 At first glance, UNCSI supports the status-based approach. Article 6(1) requires that a State respect State immunity by not exercising jurisdiction ‘in a proceeding before its courts against another State’. When read alongside Article 2(1)(b)—which clarifies that the term ‘State’ includes its central organs and, to an extent, constitutive units, agencies, instrumentalities and representatives—this aligns with the idea that State immunity depends on the sovereign status of the defendant. However, Article 6(2) introduces a significant caveat, particularly in subsection (b), which decouples immunity from the defendant's status and focuses on the subject matter of the proceedings:
A proceeding before a court of a State shall be considered to have been instituted against another State if that other State … is not named as a party to the proceeding but the proceeding in effect seeks to affect the property, rights, interests or activities of that other State.
The vagueness of the provision has drawn criticism.Footnote 25 Generally, it is unclear why State immunity should apply in cases without a named State Party. Grant suggests that the provision captures situations of ‘indirect impleading’,Footnote 26 an English law concept with limited recognition in other common law jurisdictions and virtually absent in civil law systems. This fact alone, however, suggests that indirect impleading may relate more to specific common law peculiarities than to a customary international law rule.Footnote 27 Moreover, it is debatable whether the broad text of Article 6(2)(b) accurately reflects the narrow situations associated with the English law concept of indirect impleading.
The International Law Commission's (ILC) commentary and travaux préparatoires indicate that Article 6(2)(b) was primarily intended to cover specific cases involving seizure or attachment of properties belonging to a foreign State or under its possession or control.Footnote 28 This aligns with the ‘classic example’ of indirect impleading: actions in rem against a ship owned or operated by a State.Footnote 29 Originally, this concept was introduced by the House of Lords to account for a precedent according to which actions in rem were distinct from actions in personam against property owners.Footnote 30 In proceedings against State-owned ships—where the State/owner was not considered a party—it was deemed that ‘the owner [was] at least indirectly impleaded to answer to, that is to say, to be affected by, the judgment of the Court’.Footnote 31 However, this approach was almost unique to English law. In civil law systems, where actions in rem do not exist, State immunity arises because the State/owner is the defendant in proceedings concerning its property.Footnote 32 Even common law courts have inconsistently applied indirect impleading for actions in rem and gradually moved away from it.Footnote 33 The House of Lords eventually recognized that ship owners are necessary parties to proceedings in rem,Footnote 34 rendering the logic of indirect impleading obsolete.Footnote 35
According to Grant, another case falling under Article 6(2)(b) of UNCSI is that of proceedings involving parties disputing rights or interests in property, where a third-party State asserts a right or interest in the same property.Footnote 36 However, it is unclear whether State immunity applies to all such proceedings. Support for this proposition comes from a handful of English cases whose reasoning has been much criticized.Footnote 37 While proceedings involving State-owned or controlled property may be considered equivalent to proceedings against the State, there are situations where domestic courts have exercised jurisdiction despite third-party State claims to property disputed between private parties.Footnote 38
In any event, there is virtually no practice supporting the extension of indirect impleading to situations beyond those involving third-party State property. Only a few rare dicta can be found in proceedings against former State representatives concerning their official acts.Footnote 39 According to these, foreign States would be indirectly impleaded in proceedings against their officials given that they would be expected to satisfy any award of damages.Footnote 40 However, this is an unorthodox view on the so-called ‘functional’ immunity of State officials, given the absence of a State obligation to indemnify its officials under international law.Footnote 41 The basis for this type of immunity is typically found in the fact that under international law official acts of State representatives are imputable to the State.Footnote 42 In this sense, functional immunity operates as ‘a mechanism for diverting responsibility to the State’,Footnote 43 which is the actual defendant in the proceedings.Footnote 44
There has never been a suggestion in domestic court practice that immunity should be granted due to proceedings affecting ‘interests’ or ‘activities’ of third-party States. Article 6(2)(b) of UNCSI is overinclusive in using these terms, which do not reflect customary international law and would exacerbate confusion if UNCSI were to enter into force.Footnote 45 The main issue with this provision is that it overlooks the fundamental logic governing State immunity.
The equality and independence of States prevent courts from exercising jurisdiction in a manner that compels a foreign State to exercise its sovereign authority or requires compensation for damages caused by sovereign powers.Footnote 46 However, precluding domestic courts from exercising jurisdiction in cases involving sovereign activities in general would excessively restrict the forum State's sovereignty. Often, domestic courts must make judicial determinations on the sovereign acts of foreign States to fulfil their judicial function with respect to individuals or entities within their jurisdiction.
Cases involving allegations of complicity between a non-State defendant and a third-party State serve as prominent examples. Domestic courts have frequently exercised jurisdiction over the non-State defendant, even when it required determining the responsibility of the third-party State. For instance, in the Van Anraat case, the District Court of The Hague established jurisdiction over a businessman accused of war crimes and genocide by supplying chemicals to Iraq, despite having to establish first the responsibility of principal Iraqi State officials.Footnote 47 In KPMG Peat Marwick v Davison,Footnote 48 a commission of inquiry requested documents related to transactions between New Zealand companies and a Cook Islands Government agency. The Court of Appeal of New Zealand dismissed an immunity objection based on the Cook Islands’ involvement, as they were not the focus of the inquiry and not subject to potential judgment execution.Footnote 49 In United Mexican States v British Columbia,Footnote 50 a Canadian union accused an agricultural employer of conspiring with Mexico to interfere improperly with a representation vote. The British Columbia Supreme Court rejected Mexico's immunity plea, as the legal consequences of establishing ‘improper interference’ would affect only the employer, employees and union, leaving Mexico ‘exposed to no legal consequence’.Footnote 51 In WhatsApp v NSO Group Technologies,Footnote 52 an Israeli technology company objected to US court jurisdiction, claiming its spyware technology was used by foreign governments for law enforcement activities that would be covered by immunity. The District Court for the Northern District of California rejected this plea, stating that no foreign sovereign customers would be forced to pay a judgment if WhatsApp prevailed.Footnote 53
This line of reasoning aligns with the UK Supreme Court's decision in Belhaj to reject the argument that an inquiry into the UK government's involvement in unlawful detention and mistreatment by foreign officials would ‘implead’ those foreign States.Footnote 54 Both Lord Mance and Lord Sumption agreed that State immunity did not apply because the foreign States were not parties to the case, their property was not at risk, and the relief sought would not make an impact on their legal rights or constrain their exercise of those rights.Footnote 55
In cases of complicity between a foreign State and an individual or entity within the forum, there is a compelling policy argument for the exercise of jurisdiction when relief is sought solely from the latter. This is often the only way to ensure that the party that is not entitled to immunity does not evade responsibility. For instance, in Belhaj the grant of immunity would have led to a complete absence of accountability for the British government defendants, as they would have enjoyed State immunity in other States’ courts, effectively precluding any legal action against them worldwide.Footnote 56
In sum, the idea that State immunity requires abstaining from exercising jurisdiction because deciding the claims may affect the interests and activities of third-party States is incorrect as a matter of customary international law and may lead to a lack of accountability for entities not entitled to immunity. This finding is further supported by another line of cases dealing with the activities of third-party States: those in which the legal relationship between two private parties is determined by the acts of States that are not parties to the proceedings. These cases are analysed in the following section.
III. THE PERILS OF SUBJECT-MATTER REASONING: ANCILLARY QUESTIONS AND AVOIDANCE TECHNIQUES
The doctrinal confusion surrounding the nature of State immunity risks conflating it with other doctrines focused on the subject matter of the proceedings. This risk was evident in Belhaj, where defendants argued that alongside immunity ratione personae, the principle of sovereign equality of States also includes immunity ratione materiae:
State immunity requires that the domestic courts of one state must not exercise jurisdiction over proceedings which require a ruling on the sovereign rights, interests or activities of a foreign state without its consent.Footnote 57
To bolster the argument that domestic courts must not sit in judgment where they must rule on the validity of foreign States’ sovereign acts, the defendants further cited two International Court of Justice (ICJ) cases (Monetary Gold Footnote 58 and East Timor Footnote 59) and the foreign act of State doctrine.Footnote 60
This echoes the ILC's stance in the 1996 Code of Crimes Against the Peace and Security of Mankind, according to which domestic courts lack the competence to prosecute the crime of aggression because determining individual criminal responsibility requires a preliminary finding of a State's aggression. In the ILC's view, such a determination by a national court ‘would be contrary to the fundamental principle of international law par in parem imperium non habet’.Footnote 61
The following sections demonstrate that this reasoning should be rejected as it distorts the law of State immunity, blurring the line with other doctrines that are either inapplicable to domestic courts or not mandated by international law.
A. The Inapplicability of the Monetary Gold Doctrine to Domestic Courts
The principle of consent is fundamental to international adjudication.Footnote 62 As a corollary, in the Monetary Gold case, the ICJ found that it could not adjudicate a dispute when the interests of a State not party to the proceedings formed the ‘very subject matter’ of the dispute.Footnote 63 In East Timor, the ICJ further clarified this doctrine, stating that it ‘could not rule on the lawfulness of the conduct of a State when its judgment would imply an evaluation of the lawfulness of the conduct of another State which is not a party to the case’.Footnote 64
Based on this case law, it has been suggested that the Monetary Gold doctrine should guide the application of State immunity in cases involving the rights and interests of third-party States. Alongside Belhaj, this argument was presented before the High Court of South Africa. In Cherry Blossom,Footnote 65 the Saharawi Arab Democratic Republic and the Polisario Front sought to attach a ship's cargo exporting phosphate from Moroccan-controlled part of Western Sahara, claiming that sovereignty over its natural resources belonged to the people of Western Sahara. The defendants—the owner of the ship and the private company to which the cargo had been sold—objected to the South African courts’ jurisdiction, arguing that Morocco's rights and interests were ‘indirectly impleaded’, and relied on an ‘analogous approach’ with the above-mentioned ICJ cases.Footnote 66
Both the UK Supreme Court and the High Court of South Africa rejected the analogy between State immunity and the Monetary Gold doctrine.Footnote 67 The analogy has, however, found some support in the academic literature.Footnote 68 Ruys, in particular, argued that the Cherry Blossom case bears a striking resemblance to the East Timor case, in that ‘the “very subject-matter” of the case related to the legality under international law of the conduct of a State that was not directly named as a party to the proceedings and that had not consented to those proceedings’.Footnote 69
The problem with this argument is that it ignores the essential differences between international and domestic adjudication. A test developed by an international court to deal with matters of admissibility serves a different purpose to the rules concerning the jurisdiction of domestic courts and such a test cannot be readily transposed to the domestic plane.Footnote 70 To begin with, it is unclear how this analogy should work from the standpoint of the sources of international law. Advocates of the analogy are not aided by the fact that the status of the Monetary Gold doctrine is itself contested.Footnote 71 If the doctrine embodies a customary rule resulting from the practice of States before international courts and tribunals,Footnote 72 it is of little aid in establishing the competence of domestic courts. If the doctrine is the corollary of general principles of international adjudicationFootnote 73—about which some doubts remainFootnote 74—one must be satisfied that the same considerations that determine the application of the doctrine before international courts and tribunals exist with respect to the exercise of jurisdiction by domestic courts.
In this regard, proponents of the analogy point to the similarities between State immunity and the principle of consent as the basis of the jurisdiction of the ICJ, given that both are premised on the overarching principle of sovereign equality.Footnote 75 According to Crawford, the international dispute settlement rule is ‘the nearest direct analogue in international law to the rule of State immunity’.Footnote 76 Occasionally, the allocation of competences between national and international courts—particularly the need to ensure that international disputes are resolved by judicial bodies better suited to handle inter-State claims—is also cited as a reason for the existence of State immunity.Footnote 77 Nevertheless, while these parallels suggest a connection between the considerations informing State immunity and the Monetary Gold doctrine, they do not justify the wholesale importation of the latter's test to answer questions raised by the former.
A significant distinction exists between international and domestic courts that warrants caution when comparing the procedural rules adopted in these fora. The purpose of an international court such as the ICJ is to settle international disputes.Footnote 78 The principle of consent is the sole source of its authority and provides the outer limits of its powers. Although an ICJ decision is binding exclusively ‘between the parties and in respect of that particular case’,Footnote 79 it may have further effects that pre-judge the legal position of absent third States.Footnote 80 In contrast, while domestic courts may sometimes interpret and apply international law, they cannot—without additional qualifications—settle international disputes.Footnote 81 As State organs, their powers and authority stem from their own State's sovereignty, not the consent of other States. Consequently, domestic courts have a much more limited capacity to alter the legal rights and obligations of States compared to the ICJ.
A domestic court's finding on an ancillary question concerning a third-party State, when necessary to resolve a dispute between two private parties, does not inherently implicate that State's rights and interests. As the High Court of South Africa convincingly concluded:
A finding on these issues by a South African court applying South African law, which includes customary international law …, cannot in any legal sense affect the rights of Morocco at international law.Footnote 82
In a similar vein, several scholars argue that despite the ILC's suggestion to the contrary, domestic courts remain competent to prosecute the crime of aggression.Footnote 83 While a finding that a State has committed an act of aggression indicates a violation of international law, the finding itself has no immediate legal consequences for the alleged aggressor State.Footnote 84 The increasing number of States criminalizing aggression in national laws further supports this view.Footnote 85
In general, the analogy with the Monetary Gold doctrine is deceiving because it conflates State immunity, an international law doctrine based on the status of the defendant, with the domestic law doctrine of act of State, which is linked to subject-matter considerations.Footnote 86 The following section will clarify the significance of this distinction.
B. The Act of State Doctrine as Distinguished from State Immunity
Domestic courts in several jurisdictions have developed a number of ‘avoidance techniques’ to abstain from reviewing the legality of foreign States’ activities.Footnote 87 Broadly speaking, these can be divided into two categories. First, common law courts generally avoid examining the validity of foreign States’ sovereign acts within their territory under the ‘(foreign) act of State’ doctrine.Footnote 88 Secondly, both common law and civil law courts recognize a principle of ‘non-justiciability’—sometimes encompassed within the act of State doctrineFootnote 89 or known as the ‘political question’ doctrineFootnote 90—where certain politically sensitive questions are deemed inappropriate for judicial resolution.Footnote 91
The act of State and non-justiciability doctrines share some connections with the law of State immunity. Historically, all these concepts originated from similar considerations concerning the protection of the ‘sovereign’.Footnote 92 However, their development has taken markedly different paths. State immunity has crystallized into a customary international law rule premised on the principle of sovereign equality of States and based on the status of the defendant. Conversely, act of State and non-justiciability are substantive defencesFootnote 93 based on domestic and foreign policy considerations, such as the separation of powers,Footnote 94 the propriety of judicial intervention in foreign policy matters,Footnote 95 or ‘comity and expediency’.Footnote 96 Similar considerations may equally justify judicial abstention with respect to politically sensitive decisions of the government of the forum.Footnote 97
These doctrines are thus fundamentally different from State immunity. While some courts have questioned whether these doctrines may have an international law foothold,Footnote 98 it is widely accepted that they are ‘at best permitted by international law … not based upon it’.Footnote 99 This distinction has two significant implications. First, unlike State immunity, there are considerable variations in how act of State and non-justiciability are applied by domestic courts, reflecting the ethos of each national judiciary.Footnote 100 Secondly, since act of State and non-justiciability are discretionary doctrines not subject to international legal obligations, they can often be balanced against competing public policy considerations of the forum. In particular, these doctrines are often set aside when the acts under scrutiny are manifestly contrary to established rules of international law.Footnote 101 This differs from State immunity, which cannot be disregarded even if the conduct in question involves violations of peremptory norms (jus cogens).Footnote 102
Act of State and non-justiciability are indifferent to whether proceedings are brought against the State; it is the subject matter that determines their application. Conversely, the defendant's status is a crucial factor in determining whether the rule of State immunity is engaged. Disregarding this in favour of a purely subject-matter rule would turn State immunity into a supercharged act of State doctrine without any of the counterweights of the act of State doctrine. Domestic courts would be prevented from reviewing foreign sovereign acts even if they took place within the forum State's territory. Furthermore, since domestic policy considerations cannot justify non-compliance with a State's international obligations,Footnote 103 domestic courts would be unable to exercise jurisdiction when public policy reasons warranted it. Such consequences would be bizarre and are plainly not supported by State practice.
It is not uncommon for domestic courts to examine the legality of sovereign acts of foreign States when necessary to decide a dispute between private litigants. The point was made as early as in 1892 by Von Bar:
the Courts are free to consider and pronounce an opinion upon the exercises of sovereign power by a foreign Government, if the consideration of those acts of a foreign Government only constitutes a preliminary to the decision of a question of private rights which in itself is subject to the competency of the Court of law.Footnote 104
Proceedings connected with foreign expropriations and nationalizations are a case in point. Expropriation is a quintessentially sovereign activity and there is little doubt that, if proceedings challenging the legality of these acts are brought against the expropriating State before the courts of another State, the rule of State immunity would preclude the exercise of jurisdiction.Footnote 105 However, an act of expropriation may have legal consequences for the relationships of private parties outside the territory in which the expropriation takes place. When confronted with issues of recognition of foreign expropriations in litigation among private parties, domestic courts rarely decline to exercise jurisdiction for the simple fact that the validity or legality of these acts is called into question.Footnote 106
Almost all domestic courts differentiate between the effects of these acts within the expropriating State's territory and those outside it, often refusing to recognize and enforce the latter.Footnote 107 Additionally, some decisions explicitly examine the legality of foreign expropriations, regardless of their territorial scope.Footnote 108 When confiscated property is moved to another State where legal proceedings occur, some courts refuse to review the legality of foreign expropriations.Footnote 109 However, this abstention from jurisdiction is justified not so much by an international rule of immunity, but by considerations of judicial propriety typical of the act of State doctrine.Footnote 110 As a result, if essential interests of the forum demand it, domestic courts can reassert jurisdiction. Notably, several courts have held that certain violations of international law may justify refusing to recognize sovereign acts of foreign States based on the public policy of the forum.Footnote 111 This is particularly the case with respect to grave human rights infringements or other gross violations of international law.Footnote 112
All these assessments concerning the legality of foreign expropriations under the public policy umbrella can only be premised on the assumption that there is no rule of international law preventing the exercise of jurisdiction.Footnote 113 The key distinction in this regard is between an exercise of jurisdiction against the State with respect to its sovereign acts and an exercise of jurisdiction over other entities with respect to their legal relationship as determined by the sovereign acts.Footnote 114 The rule of State immunity prohibits the former but not the latter.
In such cases, a strong policy argument favours the exercise of jurisdiction. When proceedings are brought against a foreign State regarding its sovereign activities, the territorial sovereignty of the forum State may be limited to avoid infringing the sovereignty of the defendant State. However, when the foreign State is not the defendant, no such infringement occurs. On the contrary, if the forum State were prevented from reviewing the legality of acts of foreign States, it would have to determine the legal relationship between non-State parties within its jurisdiction assuming that the acts of the foreign State were lawful. This would effectively impose the sovereignty of the third-party State over that of the forum State.Footnote 115 If State immunity is a matter of balancing competing sovereignties, it cannot be the case that one of these prevails over the other under all circumstances.
IV. CONCLUSION
The limits to the competence of domestic courts tasked with reviewing the conduct of foreign States bear upon the balance of interests that underpins the rules of State immunity; when drawing these boundaries, one must be mindful of the risks that lie at both ends. Complete disregard for the potential interference with sovereign equality and independence resulting from the exercise of jurisdiction over sovereign acts of foreign States would undermine the very raison d’être of the rules of State immunity and disrupt international intercourse. Yet, domestic courts should not relinquish their judicial function too easily when confronted with claims that their proceedings may affect foreign sovereigns, lest creating unjustifiable accountability gaps with respect to entities that are not entitled to immunity.Footnote 116
This article has demonstrated that the notion that an entity or individual not entitled to immunity may object to the jurisdiction of domestic courts by asserting that the proceedings may affect interests or activities of foreign States is based on a misapprehension of the nature of State immunity. State immunity is not a subject-matter rule that prevents courts from generally reviewing foreign sovereign acts. It is a status-based rule which exempts foreign States from judicial pronouncements that can alter their legal rights and obligations and are enforceable against them.
Attempts to dissociate State immunity from the defendant's status using ‘indirect impleading’ originate from an overly expansive interpretation of a concept created by English courts to address specific State property cases. In contrast, domestic courts in both civil and common law jurisdictions have frequently exercised jurisdiction, even when dealing with third-party States’ rights and interests. Examples include cases involving State interests in property held by private parties, cases of complicity between a private individual or entity and a foreign State, and cases where the legal relationship between private parties is determined by foreign sovereign acts, such as expropriations. Transforming State immunity into a subject-matter rule risks dangerously conflating it with unrelated doctrines, such as the Monetary Gold doctrine and the act of State doctrine. For the reasons discussed above, similar suggestions should be rejected.
In the debate concerning the competence of domestic courts with respect to rights and interests of foreign States, it is unhelpful to refer to formulas such as par in parem non habet imperium as trump cards while glossing over the complexities and contested nature of the principles governing State immunity. One must agree with Lord Mance's observation that ‘[t]he modern focus on individual rights and freedoms … makes it increasingly difficult for domestic courts simply to withdraw from adjudication upon issues arising out of State activity on the international plane’.Footnote 117 A deeper understanding of the relevant international obligations can only aid domestic courts in fulfilling their responsibilities.