1. Introduction
On 28 August 2023, in a largely unheralded development, Canada amended and substantially narrowed its unilateral declarationFootnote 1 accepting compulsory jurisdiction under Article 36(2) of the Statute of the International Court of Justice (the so-called Optional Clause).Footnote 2 Since joining the United Nations (UN) in 1945, Canada had previously always granted the International Court of Justice (ICJ) compulsory jurisdiction in relation to certain matters, albeit never in absolute terms and with further restrictions in 1970, 1985, and 1994. The current Canadian declaration differs in important ways from earlier iterations, though. The combined effects of its various limitations — notably, Canada’s new requirement that states must have provided at least six-months advance written notice before initiating ICJ claims against it, coupled with its ongoing rights to amend or terminate its declaration with immediate effectFootnote 3 — have now rendered Canadian acceptance of Optional Clause jurisdiction compulsory in name only. Canada now appears to control whether any future ICJ cases can ever be brought against it in this way.
This article addresses the context and consequences of this development, which came only two months after the Islamic Republic of Iran’s surprise initiation of Alleged Violations of State Immunities against Canada, relying on its broader previous declaration.Footnote 4 The amended 2023 Canadian declaration, however, was not unprecedented, coming instead after previous similar declarations made by the United Kingdom in 2017 and the Republic of Latvia in 2019.Footnote 5 Although this article addresses resulting issues from a Canadian perspective, its overarching concerns are also largely applicable to, and, at times, exacerbated by, these two earlier declarations.Footnote 6
Following this introduction, the second section provides a general overview of ICJ Optional Clause jurisdiction, while the third section reviews the lengthy history of its qualified acceptance by Canada. The fourth section addresses the 2023 Canadian declaration itself, along with its legal, practical, and symbolic implications, noting that any potential benefits for Canada also come with significant drawbacks. The fifth section concludes that, if Canada is unwilling to make a meaningful commitment accepting Optional Clause jurisdiction, a more effective approach would be to revoke this declaration altogether.
2. Overview of the Optional Clause
The Charter of the United Nations establishes the ICJ as the organization’s “principal judicial organ,”Footnote 7 requiring all UN member states to comply with its decisions in contentious cases involving them as parties.Footnote 8 While the Court is formally open to these and certain other states,Footnote 9 its jurisdiction over them is not automatic.Footnote 10 States must instead always consent to the exercise of ICJ jurisdiction in contentious cases involving them,Footnote 11 and this can be done in any one of four ways.Footnote 12 Three are necessarily limited: case-specific consent by disputing states through special agreement;Footnote 13 case-specific consent after the Court has received an application to initiate proceedings from another state (forum prorogatum);Footnote 14 and treaty-based consent, applicable either to treaty-specific disputes or to a broader range of legal disputes arising between particular states.Footnote 15
The fourth method allows states to accept Court jurisdiction in advance in more general terms. Article 36(2) of the ICJ Statute provides that
[t]he states parties to the present Statute may at any time declare that they recognize as compulsory ipso facto and without special agreement, in relation to any other state accepting the same obligation, the jurisdiction of the Court in all legal disputes concerning:
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a. the interpretation of a treaty;
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b. any question of international law;
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c. the existence of any fact which, if established, would constitute a breach of an international obligation;
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d. the nature or extent of the reparation to be made for the breach of an international obligation.
This provision draws on Article 36 of the Statute of the Permanent Court of International Justice. Footnote 16 In doing so, it continues to reflect a negotiated compromise between proponents and opponents of compulsory jurisdiction, allowing but not requiring states to accept it (a key reason for its ongoing characterization as the Optional Clause).Footnote 17
Formalizing this consent-based regime, states expressly accepting compulsory ICJ jurisdiction must deposit related declarations with the UN secretary-general.Footnote 18 Where applicable and still in force, previous state declarations accepting the compulsory jurisdiction of the Permanent Court of International Justice (PCIJ) are also deemed to apply to the ICJ.Footnote 19 Seventy-four states now accept compulsory ICJ jurisdiction through such declarations (or, at least, they purport to do so).Footnote 20 Though significant, it is important to note that this still comprises less than 40 percent of the 193 current UN member states.Footnote 21 The United Kingdom is the only permanent Security Council member to maintain such a declaration,Footnote 22 though, for reasons discussed below, it likely has no meaningful compulsory effect either.Footnote 23 Optional Clause declarations apply reciprocally to other states also accepting compulsory ICJ jurisdiction in this way. Although the ICJ Statute provides that they “may be made unconditionally or on condition of reciprocity on the part of several or certain states, or for a certain time,” it does not expressly delineate further acceptable limitations on potential state declarations.Footnote 24
Nevertheless, while some declarations are truly general — accepting compulsory ICJ jurisdiction in relation to any dispute with any other reciprocating state — most others are much more limited. Indeed, fifty-eight of the current seventy-four declarations contain at least one substantive reservation, often extending well beyond the limitations expressly provided for in the ICJ Statute to also include other restrictions (whether of a material, temporal, or personal nature).Footnote 25 Qualifying Optional Clause declarations with substantive reservations is an accepted practice with a lengthy history. The League of Nations supported it as a mechanism to encourage greater state acceptance of compulsory PCIJ jurisdiction.Footnote 26 This practice has continued in relation to the ICJ, reflecting the consent-based nature of Optional Clause jurisdiction.Footnote 27 The Court itself has opined that declarations “are facultative, unilateral engagements, that States are absolutely free to make or not to make. In making the declaration a State is equally free either to do so unconditionally and without limit of time for its duration, or to qualify it with conditions or reservations.”Footnote 28
The ICJ Statute empowers the Court to determine the extent of its own jurisdiction if it is challenged (for example, by a state seeking to rely upon a reservation to constrain it).Footnote 29 Using this authority, the Court has sustained substantive reservations to Optional Clause declarations in various contentious cases, thereby precluding its own jurisdiction to assess the legal merits of the underlying disputes.Footnote 30 For example, a 1994 Canadian reservation prevented the Court from exercising jurisdiction in the Fisheries Jurisdiction case, as discussed in greater detail in the following section.Footnote 31 For the ICJ, the key issue is whether — at the time that a specific contentious case is initiated — the states involved have accepted its related jurisdiction.Footnote 32 The legal merits of the case itself are not material to this jurisdictional assessment; instead, the Court recognized in Fisheries Jurisdiction that
a reservation to a declaration of acceptance of the compulsory jurisdiction of the Court is to be interpreted in a natural and reasonable way, with appropriate regard for the intentions of the reserving State and the purpose of the reservation. In point of fact, reservations from the Court’s jurisdiction may be made by States for a variety of reasons; sometimes precisely because they feel vulnerable about the legality of their position or policy.Footnote 33
Subsequent ICJ decisions addressing reservations to Optional Clause declarations have continued to examine subjective intent alongside textual considerations. For example, in Aerial Incident of 1999, the Court emphasized the importance of “the intention of a declarant State, as expressed in the actual text of its declaration” before concluding that “India has repeatedly made clear that it wishes to limit in this manner the scope ratione personae of its acceptance of the Court’s jurisdiction. Whatever may have been the reasons for this limitation, the Court is bound to apply it.”Footnote 34 Substantive reservations do not just “benefit” the reserving states though. They also apply reciprocally, limiting the ability of these states to bring related ICJ cases against other states, even those with broader declarations that would otherwise allow such cases to proceed.Footnote 35 However, this reciprocity does not extend to the formal conditions established by individual states for the potential amendment or withdrawal of their declarations.Footnote 36 Some states reserve the right to do so unilaterally with immediate effect, while others restrict their own future changes in various ways (for example, by establishing waiting periods before they are given effect).Footnote 37 So long as contesting states have consented to Court jurisdiction in a specific case, variations in their legal rights to subsequently alter their declarations will not affect this determination. In any event, changes taking effect after the Court has already established jurisdiction in a case will not affect its continued exercise in that case.Footnote 38
Of the seven ICJ cases brought by or against Canada to date, three have involved Optional Clause jurisdiction — cases initiated by Spain in 1995,Footnote 39 the Federal Republic of Yugoslavia (FRY) in 1999,Footnote 40 and Iran in 2023,Footnote 41 respectively.Footnote 42 As mentioned, the Court rejected jurisdiction over the Spanish claim due to a Canadian reservation. It also dismissed the FRY’s claim but for jurisdictional reasons unrelated to Canada. The latter case is ongoing. All three cases will be discussed in greater detail in the following section. Canada has never relied upon Optional Clause jurisdiction to initiate an ICJ case against another state.
3. Pre-2023 Canadian Optional Clause Declarations
Canada has been a UN member state — and, therefore, a party to the ICJ Statute Footnote 43 — since its ratification of the UN Charter on 9 November 1945. Since that time, Canada has also always subjected itself to compulsory ICJ jurisdiction through related declarations, albeit never without significant restrictions. Initially, this acceptance rested on the deemed extension of its 1930 PCIJ declaration, which was already limited in various ways.Footnote 44 It only applied “until such time as notice may be given to terminate the acceptance” (following an initial ten-year commitment that expired in 1940) and only to “disputes arising after ratification … with regard to situations or facts subsequent to said ratification.”Footnote 45 Apart from one restriction specific to the League of Nations,Footnote 46 the other substantive reservations established in this initial PCIJ declaration also continued with respect to the ICJ, precluding compulsory jurisdiction over disputes involving:
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• other agreed methods of dispute settlement;Footnote 47
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• other Commonwealth members;Footnote 48 and
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• situations solely within Canada’s domestic jurisdiction.Footnote 49
This declaration, however, was never relied upon to establish PCIJ or ICJ jurisdiction in a contentious case, whether by or against Canada.
It remained in force until 7 April 1970 when Canada amended and further narrowed its acceptance of compulsory jurisdiction with a new — and, this time, ICJ-specific — declaration.Footnote 50 This same date was established by Canada as the revised stale date for disputes and related facts and situations, bringing it forward four decades from the date of the PCIJ declaration.Footnote 51 This 1970 declaration maintained Canada’s right to withdraw its acceptance of compulsory ICJ jurisdiction, but, unlike its PCIJ declaration, it did not include an initial irrevocable fixed time commitment.Footnote 52 This time, Canada also expressly reserved the right “to add to, amend or withdraw” any reservations established by or subsequent to the new declaration, with immediate effect, upon notification of the UN secretary-general.Footnote 53 Arguably, however, this latter right was already implicit in the earlier overarching right of withdrawal, as demonstrated by Canada’s very use of this new and more restrictive declaration to withdraw its initial PCIJ acceptance with immediate effect.Footnote 54
With minor language modifications, the 1970 declaration maintained the three prior substantive Canadian reservations relating to other agreed dispute settlement methods,Footnote 55 Commonwealth states,Footnote 56 and exclusive domestic jurisdiction.Footnote 57 It also added another one, rejecting compulsory ICJ jurisdiction over “disputes arising out of or concerning jurisdiction or rights claimed or exercised by Canada in respect of the conservation, management or exploitation of the living resources of the sea, or in respect of the prevention or control of pollution or contamination of the marine environment in marine areas adjacent to the coast of Canada.”Footnote 58 With this new restriction, Canada sought mainly to insulate itself from legal claims arising from legislative measures managing its coastal fishing zones and controlling Arctic pollution.Footnote 59 In a related statement to the Canadian House of Commons, then Prime Minister Pierre Trudeau expressly noted that the new reservation to Canada’s Optional Clause declaration
is intended to guard against any possible litigation of certain features of these two bills. Canada strongly supports the rule of law in international affairs. … Canada is not prepared however to engage in litigation with other states concerning vital issues where the law is either inadequate or non-existent and thus does not provide a firm basis for judicial decision.Footnote 60
He nonetheless expressed hope that new international rules would soon be agreed and that the reservation would therefore only be temporary.Footnote 61
Canada did in fact remove this reservation when it submitted its next amended declaration on 10 September 1985 (while maintaining the other three substantive reservations relating to other agreed dispute settlement methods, Commonwealth states, and exclusive domestic jurisdiction, respectively).Footnote 62 Removing this reservation may not have fully reflected the spirit of Trudeau’s commitment though. In its only other major revision from the 1970 version, the amended declaration once again brought forward the applicable stale date, also to 10 September 1985.Footnote 63 This precluded compulsory ICJ jurisdiction over earlier disputes and those concerning earlier facts or situations — including, at least arguably, the Canadian extension of coastal fishing zone protections and adoption of pollution control measuresFootnote 64 — without Canada having to maintain specific related substantive reservations. In any event, this was never judicially tested. No ICJ cases were brought by or against Canada pursuant to its 1970 or 1985 Optional Clause declarations.
Canada submitted another revised declaration less than nine years later on 10 May 1994.Footnote 65 The stale date was again advanced to this same date.Footnote 66 In its only other substantive change from the 1985 declaration, Canada also added a new reservation rejecting compulsory ICJ jurisdiction over “disputes arising out of or concerning conservation and management measures taken by Canada with respect to vessels fishing in the NAFO [Northwest Atlantic Fisheries Organization] Regulatory Area, as defined in the Convention on Future Multilateral Co-operation in the Northwest Atlantic Fisheries, 1978, and the enforcement of such measures.”Footnote 67 Prior substantive reservations relating to other agreed dispute settlement methods, Commonwealth states, and exclusive domestic jurisdiction were retained, along with the rights of immediate withdrawal and amendment.Footnote 68
The new reservation anticipated the coming into force of controversial amendments to Canada’s Coastal Fisheries Protection Act, which occurred just two days later.Footnote 69 Among other things, this Canadian legislation and its subsequent implementing regulations established prohibitions and authorized related enforcement, applicable to certain (over-)fishing activities taking place beyond the 200-nautical mile limit of Canada’s claimed fisheries zones.Footnote 70 In March 1995, Canadian officials exercising this domestic authority boarded a Spanish-flagged fishing trawler on the high seas and forced it into a Canadian port. The ICJ subsequently relied upon Canada’s invocation of its NAFO fisheries reservation to reject Optional Clause jurisdiction in the related Fisheries Jurisdiction case brought by Spain.Footnote 71 This prevented a final and binding Court assessment of the international legal merits of Canada’s enforcement actions, which remain controversial.Footnote 72 To date, this is the only time that the Court has rejected Optional Clause jurisdiction due to a Canadian reservation. The 1994 Canadian declaration has nonetheless been implicated twice more in ICJ proceedings. In the next case, Legality of Use of Force, brought by the FRY in 1999, the ICJ also refused jurisdiction but not because of Canadian reservations. Instead, the Court determined that the FRY itself was not a UN member state or party to the ICJ Statute at the material time.Footnote 73
Jurisdiction has not yet been assessed in the final case, Alleged Violations of State Immunities, brought by Iran on 27 June 2023.Footnote 74 If the case continues, though, its establishment seems likely as both states appear to have accepted it at the time the case was initiated. Just one day before doing so, Iran had deposited its first Optional Clause declaration in over seventy years, albeit “only in relation to the following disputes: (i) the jurisdictional immunities of the State and State property; [and] (ii) immunity from measures of constraint against State or State property.”Footnote 75 As two commentators noted, the timing and very limited scope of this acceptance certainly “gives the impression that it was tailor-made for the present proceedings.”Footnote 76 However, even if this is true, the Court’s own past practice strongly suggests that this will not bar it from exercising related jurisdiction.Footnote 77 In particular, the Court recognized in Right of Passage that
a State accepting the jurisdiction of the Court must expect that an Application may be filed against it before the Court by a new declarant State on the same day on which that State deposits with the Secretary-General its Declaration of Acceptance. It is on that very day that the consensual bond, which is the basis of the Optional Clause, comes into being between the States concerned.Footnote 78
4. 2023 Canadian declaration
Canada submitted its most recent Optional Clause declaration just two months later on 28 August 2023. This version maintained all restrictions included in the 1994 Canadian declaration — namely, its four listed substantive reservations (relating to other agreed dispute settlement methods, Commonwealth states, exclusive domestic jurisdiction, and NAFO-regulated fisheries, respectively), rights of withdrawal and amendment with immediate effect, and, in a break with past practice, even the stale date of 10 May 1994.Footnote 79 However, as outlined below, Canada also added two new reservations that, in conjunction with these earlier limitations, now render its continued acceptance of compulsory ICJ jurisdiction illusory.
The first new Canadian reservation is an ‘anti-ambush’ protection precluding ICJ jurisdiction in two specific situations:
[D]isputes in respect of which any other party to the dispute has accepted the compulsory jurisdiction of the International Court of Justice only in relation to or for the purpose of the dispute; or where the acceptance of the Court’s compulsory jurisdiction on behalf of any other party to the dispute was deposited or ratified less than twelve months prior to the filing of the application bringing the dispute before the Court[.]Footnote 80
Although restrictive, there is a lengthy history of states making such reservations, and the Court has recognized their ability to do so.Footnote 81
Canada’s second new reservation is both more consequential and less well established. It excludes from compulsory ICJ jurisdiction “disputes or claims in respect of which the dispute or claim in question has not been notified to Canada by the State or States concerned in writing, including of an intention to submit the dispute or claim to the Court failing an amicable settlement, at least six months in advance of the submission of the dispute or claim to the Court[.]”Footnote 82 This required notification period could provide Canada with opportunities for negotiated dispute settlement prior to facing disruptive and costly litigation;Footnote 83 however, when combined with its rights to withdraw or amend its declaration with immediate effect, this reservation also appears to establish a minimum six-month window for Canada to forestall any potential ICJ claim against it, should it wish to do so (regardless of whether the underlying dispute is settled by other means).Footnote 84
At any time during this notification period, Canada could submit a revised declaration specifically tailored to prevent Court jurisdiction in any related dispute — for example, with a new reservation aimed either at the state or the subject matter in questionFootnote 85 — or it could withdraw its declaration altogether. Put another way, despite maintaining an Optional Clause declaration, Canada now appears able to reject related Court jurisdiction on a dispute-specific basis, even after being formally notified of impending litigation against it. Exercised or not, this apparent unilateral Canadian control over whether Optional Clause cases can proceed seems antithetical to any meaningful advance acceptance of compulsory dispute settlement. These issues, and their potential implications, are discussed in more detail below.
A 2017 amendment to the UK declaration contains the earliest precedent for this reservation.Footnote 86 It was copied almost verbatim by Canada in 2023,Footnote 87 having been previously copied by Latvia in a 2019 revision of its own declaration.Footnote 88 In a 2017 statement to the UK House of Commons, Sir Alan Duncan, then minister of state for foreign and commonwealth affairs, offered the following explanation for this UK notification requirement:
This would provide an opportunity for diplomatic engagement with the State concerned. The prior notification of a claim is an established part of domestic dispute resolution in the United Kingdom, as well as being a feature of the dispute settlement provisions in many international treaties. The judgment of the ICJ in the nuclear disarmament case[Footnote 89] accepted that a State must be made aware that litigants have opposing views, otherwise a respondent State does not have the opportunity to react to those opposing views before the institution of proceedings against it. The revised Declaration incorporates the UK position that was advanced in the proceedings that prior notification of the kind described is an appropriate step before an application instituting proceedings, seising the Court, can be submitted.Footnote 90
This offers a principled justification for the UK reservation when viewed in isolation. Indeed, it appears consistent with the ICJ’s own more limited position in Nuclear Disarmament, and in an earlier case, that, while an underlying legal dispute must exist before it can exercise related jurisdiction, prior notification of a specific intent to initiate Court proceedings is not required unless an applicable Optional Clause declaration establishes otherwise.Footnote 91
However, the UK statement did not address the implications of this change when combined with its other restrictions on compulsory ICJ jurisdiction. Like Canada, the United Kingdom also expressly retains rights to withdraw or amend its declaration with immediate effect.Footnote 92 As a result, and for the same reasons noted above, its notification requirement has attracted some scholarly criticism. For example, Geir Ulfstein argues that “the UK’s declaration no longer meaningfully can be seen as compulsory in a legal sense.”Footnote 93 Mauro Barelli echoes this conclusion, noting that “the UK declaration includes a number of particularly controversial conditions and limitations that hardly match its pro-rule of law rhetoric and amount to a de-facto ‘exit’ from the system of compulsory jurisdiction.”Footnote 94
Canada did not widely publicize the recent amendments to its own Optional Clause declaration, let alone the rationale underpinning them. Indeed, no contemporaneous Canadian statement concerning the 2023 declaration appears to have been made at all, beyond the formal notice provided to, and then subsequently circulated by, the UN secretary-general.Footnote 95 However, in February 2024, the new notification reservation was discussed before the Standing Senate Committee on Foreign Affairs and International Trade after a committee member questioned its potential effects on international dispute settlement.Footnote 96 In response, a senior Canadian official asserted that it “encourages states to sit down and have a period of time to discuss the object of the dispute before going to the court immediately,” noting that this could also help to conserve limited ICJ resources.Footnote 97 He added that “countries like Canada are, obviously, mindful of protecting the integrity of the jurisdiction of the court to make sure that it is able to play its role when it’s time for it to play its role,” suggesting that this would follow unsuccessful negotiations.Footnote 98 However, this Canadian explanation (like that of the United Kingdom) did not address the effects of this new reservation when combined with its other restrictions on the acceptance of compulsory Court jurisdiction. Despite a general assurance that this reservation “is in no way meant to make it more difficult to find peaceful settlement of disputes,” no ICJ-specific commitment was made to refrain from amending or withdrawing Canada’s Optional Clause declaration during the notification period.Footnote 99
The recent amendments to the Canadian declaration were clearly influenced by the earlier UK precedent;Footnote 100 however, the context certainly suggests that Canada also made them, at least in part, in reaction to Iran’s initiation of Alleged Violations of State Immunities just one day after its narrow acceptance of Optional Clause jurisdiction. That said, they will not retroactively preclude Court jurisdiction in these proceedings. Since these Canadian changes only apply to cases initiated after the 2023 declaration, their potential rationale must be viewed in this light — that is, as a way to avoid surprise and otherwise manage future ICJ cases brought against Canada. Alleged Violations of State Immunities nonetheless serves as a useful illustration of their possible implications. For example, had it applied, the Canadian anti-ambush protection alone would have required Iran to wait at least twelve months following its declaration before initiating its case, and, even then, its apparent dispute-specific nature might well have been a jurisdictional barrier. Iran would also have had to provide Canada with at least six months written notice of both the dispute and its intention to submit an ICJ claim failing an amicable settlement. This would have provided Canada with an opportunity to formally respond to specific Iranian claims, and would have given both states a negotiating window to address them, prior to any potential ICJ engagement. However, it would also have permitted Canada to unilaterally revoke related Court jurisdiction by amending or withdrawing its Optional Clause declaration during this notification period.Footnote 101 This is particularly noteworthy as it is not obvious that Canada will prevail if this case is ultimately decided on its legal merits.Footnote 102
It is unclear whether future litigation risks prompted the 2023 Canadian amendments. Some were certainly foreseeable, though. Notably, earlier that same year, the UN General Assembly had requested an ICJ advisory opinion on the climate-related international legal obligations of states and the potential legal consequences of related harmful acts and omissions.Footnote 103 Considerable uncertainty therefore surrounded these legal issues when Canada revised its declaration less than five months later. Although the resulting 2025 advisory opinion is not directly binding on states, it did recognize that potential state legal responsibility for such harm can arise not only from treaty obligations but also from various customary international law principles.Footnote 104 The risks of adverse legal findings in future related contentious cases could therefore be significant, particularly as some estimates of climate-related harm already exceed one hundred billion dollars annually.Footnote 105 Whether intentional or not, Canada’s current restrictions now seem to allow it to control whether any such Optional Clause cases can ever be brought against it.Footnote 106
A. (Other) legal implications
The 2023 Canadian declaration nevertheless does still have some residual legal effect. Other reciprocating states can continue to rely on it to establish ICJ jurisdiction in contentious cases, should Canada choose not to amend or withdraw its declaration within the mandatory notification period. Indeed, the declaration still provides a basis for these states to initiate claims and to request legally binding provisional measures, if not necessarily to receive them, even if current or future Canadian reservations are invoked by Canada and ultimately preclude Court jurisdiction to assess their merits.Footnote 107
Canada can also still bring cases against such states; however, its ability to do so will be limited by the reciprocal application of its own substantive reservations, in addition to those found in the opposing state’s declaration. Among other things, this will likely now require Canada to provide at least a six-month written notice before initiating any such claim or risk a related challenge to ICJ jurisdiction by the opposing state (since this appears to involve a substantive jurisdictional restriction, subject to reciprocity, rather than a formal condition of the Canadian declaration, such as the right of immediate withdrawal). The United Kingdom appears to accept this in relation to its own notification requirement: immediately following discussion of this specific reservation, its 2017 parliamentary statement noted that “[t]he United Kingdom would be held to the terms of the new Declaration in respect of any proceedings that it may wish to institute. The Government is content to be held to this standard.”Footnote 108
However, reciprocal application of the notification requirement would not necessarily mean that other states could pre-empt compulsory ICJ jurisdiction. This only results in conjunction with a right to amend or withdraw declarations with immediate effect (or otherwise during the notification period). Unlike Canada and the United Kingdom, not all states expressly maintain the latter rights.Footnote 109 In fact, many states have formally established six-month waiting periods before changes to their Optional Clause declarations take effect.Footnote 110 The ICJ has previously characterized such unilateral restrictions as “inescapable” binding obligations.Footnote 111 Since reciprocity does not extend to these procedural rights either, it appears that at least some states would have difficulty preventing contentious cases going forward, even with advance notice.Footnote 112
The legal validity of the 2023 Canadian declaration has not been tested. No contentious cases have been initiated on its basis, nor has the ICJ been called upon to assess related UK or Latvian reservations. Challenging it may nonetheless prove difficult. The ICJ has previously observed that reservations “operate to define the parameters of the State’s acceptance of the compulsory jurisdiction of the Court. There is thus no reason to interpret them restrictively.”Footnote 113 Instead, they “should be interpreted in a manner compatible with the effect sought by the reserving State.”Footnote 114 As it stands, the Canadian declaration does still constitute prima facie acceptance of compulsory Court jurisdiction following the notification period (albeit with considerable other restrictions). Applying this notification requirement would not appear to raise serious interpretive concerns on its own. It is unambiguous: Canada does not accept compulsory Court jurisdiction in cases initiated against it without at least six months prior written notice. The straightforward application of this reservation therefore seems likely to prevent such cases from proceeding, at least without its consent.Footnote 115 Similarly, it will clearly not bar Court jurisdiction in cases initiated after this notice period has elapsed.
Doing so would instead require an additional formal step — that is, amendment or withdrawal of the 2023 Canadian declaration prior to the end of the six-month notification period. Here too, Canada has unambiguously claimed the right to do so, with immediate effect. While Barelli notes that a “courageous Court” might still seek to impose a notice requirement on a state expressly reserving a right to amend or withdraw its declaration with immediate effect, this is difficult to reconcile with the voluntary nature of the Optional Clause system and the Court’s own related jurisprudence.Footnote 116 A good faith requirement of reasonable notice before withdrawal becomes effective only seems to apply when a declaration does not otherwise establish applicable timelines.Footnote 117 The Court has previously observed, in Military and Paramilitary Activities in and against Nicaragua, that states “may specify how long the declaration itself shall remain in force, or what notice (if any) will be required to terminate it.”Footnote 118 More recently, in 2016, the Court expressly recognized in Alleged Violations of Sovereign Rights and Maritime Spaces in the Caribbean Sea that “[i]n its declaration under Article 36, paragraph 2, a State is free to provide that that declaration may be withdrawn with immediate effect.”Footnote 119
If Canada exercises this right during the required notification period, and it either does not replace its declaration or does so with a new dispute-specific reservation, it would appear to bar the ICJ from proceeding with any future related case.Footnote 120 Although Barelli has raised “good faith” concerns over related UK reservations, he still notes that “the practice of modifying a declaration with the sole purpose of preventing unwanted litigation may well stand the Court’s test of acceptability.”Footnote 121 This situation is not dissimilar to the operation of an anti-ambush reservation in conjunction with a right of amendment or withdrawal with immediate effect.Footnote 122 Requiring other states to delay initiating legal claims for a period of time after making their declarations also allows reserving states to pre-emptively revoke related Court jurisdiction, should they wish.Footnote 123 The general notice provided to them is simply less detailed, concerning potential future litigants rather than specific legal disputes. In practice, this may be a distinction without much difference, particularly in the context of ongoing bilateral disagreements.
Indeed, absent any applicable substantive reservations, a right of immediate withdrawal alone can still offer states considerable control over some legal disputes. Any efforts by other states to settle such disputes without resorting to litigation could still raise the risk of possible future ICJ claims and provide a window to prevent them (albeit one of indeterminate length). This potential for pre-emptive withdrawal has led to significant academic criticism of this right, both for restricting Optional Clause jurisdiction and for potentially discouraging diplomatic and other non-judicial dispute settlement efforts prior to litigation.Footnote 124 The Court has nonetheless expressly recognized that states may retain this right.Footnote 125 In fact, rights of withdrawal and amendment have already been relied upon by various states to obviate Court jurisdiction in specific anticipated cases against them.Footnote 126
The past practice of the ICJ indicates that it will seek to give effect to the declarant state’s intentions, even if this nullifies its own resulting jurisdiction.Footnote 127 Indeed, the Court has expressly recognized that reservations can remain valid even if they are specifically designed to shield legally questionable actions from its review.Footnote 128 An affected state might nonetheless still challenge any Canadian right to withdraw or amend its Optional Clause declaration during the mandatory notification period, with immediate effect, as contrary to the ICJ Statute. Robert Kolb, for example, implies that reserving such a right would be “toxic” to the law underpinning ICJ jurisdiction.Footnote 129 It is unclear how the Court would respond to such arguments since it has not previously addressed this issue or its implications.Footnote 130 However, various scholars maintain that reservations conflicting with the ICJ Statute should be considered invalid, and this has also been argued, at times, by individual members of the Court.Footnote 131
That said, it does not necessarily follow that any aspects of the current Canadian declaration, or any subsequent changes relying upon it, would be considered legally incompatible with the ICJ Statute. A restriction directly impinging on the competence of the ICJ to determine its own jurisdiction would appear to raise greater concerns; for example, a “self-judging” reservation — such as one rejecting Court jurisdiction over matters that a state “considers to be” within its domestic jurisdiction — purports to allow the state itself to make such a determination, rather than the Court, potentially even after the latter has been validly seized with a dispute.Footnote 132 In contrast, the Canadian restrictions are capable of objective assessment upon the initiation of a case, albeit in a way that would then seemingly preclude related Court jurisdiction. Other (hypothetical) reservations raising serious incompatibility concerns might include those seeking to limit “the functioning and the organization of the Court.”Footnote 133 The Canadian restrictions do not have this effect either. Nonetheless, some scholars also argue that the absence of meaningful compulsory effect should be considered a potential ground for invalidity in its own right (since the express purpose of Optional Clause declarations is to recognize compulsory ICJ jurisdiction).Footnote 134
Even if the Court were to characterize these Canadian restrictions as invalid, though, the absence of related legal precedent still leaves the likely effects of such a determination uncertain. In particular, would the Canadian declaration itself be void of legal effect or simply the offending reservations (for example, the right to withdraw or amend it during the required notification period with immediate effect), leaving the overall acceptance of compulsory jurisdiction intact? Academic debate remains on this general point;Footnote 135 however, the latter option seems difficult to reconcile with the Court’s overarching views, at least to date, concerning the underlying importance of state consent to Optional Clause jurisdiction and the effect of related restrictions.Footnote 136 The absence of a valid declaration would also then remove any basis for the exercise of Optional Clause jurisdiction by the Court.Footnote 137
Given these various considerations, if Canada does amend or withdraw its declaration during the notification period — specifically intending to bar the Court from proceeding with a case that has not yet been initiated (or for which the required notice was not provided) — it would likely take a “courageous Court” indeed to still exercise jurisdiction over it. While this possibility cannot be wholly discounted, it does seem remote.
The lack of Optional Clause jurisdiction should nonetheless not be equated with legal impunity. Limited or not, such declarations are not the only way to establish ICJ jurisdiction in contentious cases (and, depending upon the subject matter and states concerned, other dispute settlement bodies may also have jurisdiction). Only about one in three ICJ cases have been initiated on this basis. The majority have instead relied upon ad hoc jurisdictional acceptance or, more frequently, the unilateral invocation of applicable treaty provisions.Footnote 138 In practice, the latter is the most important basis of compulsory Court jurisdiction.Footnote 139 In principle, state international legal obligations also remain the same, whether the ICJ can assess them or not, including underlying secondary obligations to comply and to provide remedies to injured states in the event of breach.Footnote 140 Disagreements concerning the interpretation and application of these obligations do seem more likely without potential third party review, though, whether in good faith or otherwise.
B. Practical implications
Canada now appears to control whether specific Optional Clause cases can be brought against it, even after other states have formally notified it of their intention to do so. However, although this unilateral control could lead to beneficial practical effects for Canada, these cannot necessarily be presumed. For example, as previously noted, the reciprocal application of Canada’s notification requirement could substantially restrict its own ability to initiate future ICJ cases against other states, particularly those with express rights to amend or withdraw their own declarations with immediate effect.
Canada has implied that this new requirement could facilitate international dispute settlement by providing an opportunity to begin negotiations prior to Court involvement (as has the United Kingdom). Formal notice from another state of a specific legal dispute, and a desire to settle it, could certainly have this effect. However, given Canada’s (or, in the case of Canadian claims, the other state’s) ability to prevent subsequent ICJ involvement, any resulting bilateral negotiations would not be conducted knowing that failure to agree could lead instead to compulsory dispute settlement. This may remove a significant impetus for compromise — for example, by allowing the disputing states to continue to rely on their own legal interpretations, regardless of their objective merits, without concern for how they might later appear to the ICJ.Footnote 141
During the notification period, the only practical barrier to Canada revoking compulsory ICJ jurisdiction is the requirement to amend or withdraw its declaration for this purpose. It appears to retain the legal right to do so with immediate effect. Indeed, the narrow six-month window in which this right applies may even incentivize invoking it before difficult negotiations can be concluded. From a domestic perspective, however, this limited time frame would likely not curtail Canada’s ability to alter its declaration; this would fall within federal executive authority as an exercise of the Crown’s prerogative over foreign affairs rather than requiring additional legislative involvement.Footnote 142 Doing so will likely still have significant international political costs, though, which would be payable every time this case-specific right is exercised.Footnote 143 Here, it is worth noting that, while another state threatening to initiate an ICJ claim may be perceived as hostile, this is not the only way to view it. It also signals a state’s readiness to submit to peaceful and legally binding dispute settlement.Footnote 144 The closure resulting from accepting such a settlement process might well strengthen broader bilateral relationships.Footnote 145 Actively preventing it, with a dispute-specific restriction of ICJ jurisdiction, seems less likely to do so (though Canada has signalled its ongoing commitment to peaceful dispute settlement despite its new reservations).
Regardless, Canada can now protect itself against Optional Clause cases where the anticipated financial, political, or other costs of losing are perceived as too high.Footnote 146 Not exercising this right may therefore prove difficult, particularly when its underlying legal case is weak or uncertain, which might well be anticipated when other states initiate ICJ cases against it. For example, it is not hard to imagine that Canada would have prevented Alleged Violations of State Immunities from proceeding had it been able to do so. This control could allow Canada to insulate policies that clearly violate international law from binding ICJ review, though they would nonetheless remain prohibited and might still have other significant domestic and international consequences. Perhaps as importantly, in practice, this also allows Canada to continue to rely on its own legal interpretations and assessments in areas where underlying international obligations remain ambiguous. Indeed, Canada’s 1970 fisheries reservation was essentially justified on this basis. Put simply, avoiding situations where the Court can expressly characterize its preferred policy options as illegal, in final and binding judgments, will afford Canada greater policy flexibility.Footnote 147
Realistically, though, it is still important to recognize that the current Canadian declaration is unlikely to forestall many actual ICJ proceedings. As noted, Optional Clause jurisdiction is not frequently invoked, though it is impossible to know how many Court claims are never pursued at all in the face of clearly applicable reservations. Nonetheless, between 1930 and 2023, only three states initiated cases against Canada relying upon its more permissive, albeit still limited, prior declarations. Canada has never done so against another state.
C. Symbolism
The significance of the 2023 Canadian declaration may therefore be as much symbolic as practical. Responding to Iran’s initiation of Alleged Violations of State Immunities, Canada issued a statement noting, among other things, that “[w]e strongly believe in the role of the International Court of Justice as a crucial platform for the peaceful settlement of disputes in accordance with international law.”Footnote 148 Since amending its declaration, Canada has continued to highlight its “unwavering support for international law and the ICJ.”Footnote 149 However, despite these assertions, its recent declaration could nonetheless still undermine Canada’s (self-)image as a strong proponent of the Court.Footnote 150 A limited declaration is not a direct attack on the international rule of law itself, though, and should not be seen as such. States are not legally required to make such declarations, and most have not. For the minority that have, doing so with extensive substantive and procedural limitations is a common and accepted practice.
The symbolic implications for Canada itself should therefore not be overstated. Indeed, its acceptance of compulsory ICJ jurisdiction has always been somewhat illusory. For example, since 1930, Canada has continuously maintained a Commonwealth reservation; this alone now precludes fifty-five UN member states — over 25 percent of the organization’s membership — from initiating Optional Clause cases against it.Footnote 151 Canada has already used other reservations — in 1970 and again in 1994 — to deliberately shield controversial state conduct from ICJ review. In some ways, the 2023 declaration is simply an extension of this historical practice, allowing future reservations to be made by Canada on a dispute-specific basis. To date, this revision does not appear to have attracted significant state or civil society criticism of Canada.
The impact of this declaration may instead be borne largely by the ICJ, particularly since the United Kingdom and Latvia also maintain similar restrictions. In effect, three states with Optional Clause declarations now appear able to withdraw or amend them, with immediate effect, even after other states — also with pre-existing declarationsFootnote 152 — have formally notified them of their intent to initiate Court proceedings in relation to specific legal disputes. As discussed, an anti-ambush provision or even just a right of immediate withdrawal could sometimes lead to a similar result. However, unlike these latter situations, the current Canadian, UK, and Latvian declarations effectively require other states to provide such notice — and then allow it to be used against them at any time over the next six months — thereby both formalizing and enhancing the ability of Canada, the United Kingdom, and Latvia to choose which specific cases can proceed against them, if any. This renders the Optional Clause system little more than a complicated mechanism to establish forum prorogatum jurisdiction.Footnote 153
This may in turn lead other states to adopt similar restrictions in their own declarations, just as the United Kingdom clearly inspired both Latvia and Canada. In fact, the advance notification reservation has already been copied again. Poland revised its Optional Clause declaration on 10 July 2024 to include such a reservation, effective on 10 January 2025.Footnote 154 In a noteworthy legal difference, though, it did not also reserve rights to amend or withdraw its declaration with immediate effect; instead, related changes will only take effect six months following notification of the UN Secretary-General.Footnote 155 This still establishes a window to pursue amicable dispute settlement prior to litigation; however, Poland does not appear to retain any corresponding legal right to reject compulsory Court jurisdiction during this period, unlike Canada, Latvia, and the United Kingdom.
Despite this example, one might reasonably expect other states with current Optional Clause declarations to consider establishing rights to amend or withdraw them with immediate effect, if they have not already done so (regardless of whether they also establish prior notification requirements of their own). States contemplating initial declarations might also be more likely to do so, though this is often already the case.Footnote 156 Otherwise, Canada, Latvia, and the United Kingdom will each be able to initiate compulsory cases against them without being subject to the same reciprocal risk.Footnote 157 When notified of potential litigation by one of these three states, it is also reasonable to expect that other states with rights of immediate withdrawal or amendment might then consider restricting their own declarations to prevent it.
These three declarations have already strengthened an apparent ongoing shift towards limited, dispute-specific acceptance of Optional Clause jurisdiction over the past decade.Footnote 158 Indeed, only two states without pre-existing declarations have agreed to it in the past ten years: Iran and Equatorial Guinea, the latter also doing so with an extremely narrow declaration.Footnote 159 That said, both of these states have nonetheless still accepted compulsory ICJ jurisdiction in advance in relation to certain disputes. The new Canadian, UK, and Latvian declarations are arguably even more restrictive since they no longer appear to have any meaningful compulsory effect at all, instead allowing for unilateral dispute-specific rejection of Court jurisdiction, regardless of the opposing state or subject matter in question.
5. Conclusion
Canada’s acceptance of Optional Clause jurisdiction has always been more limited than it appeared. This is not unlawful. States are not required to do so at all. As written, though, the 2023 Canadian declaration renders this commitment illusory. Reasonable observers might disagree over whether Canada should have limited its acceptance of compulsory ICJ jurisdiction to this extent. Indeed, as a proponent of the Court and its “crucial” role in international dispute settlement, Canada should likely reconsider having done so. A simple fix to the most serious concerns identified in this article would be for Canada to renounce any ongoing right to revoke related ICJ jurisdiction once it has been formally notified by another state of impending litigation relating to a specific dispute. It is nevertheless difficult to foresee this reversal, particularly if Alleged Violations of State Immunity is decided against Canada on the merits.
The status quo appears to allow Canada to decide for itself whether any new Optional Clause cases can proceed against it. Canada could therefore wait to further restrict its formal acceptance of ICJ jurisdiction until it perceives a dispute-specific need to do so. Given the limited number of Optional Clause cases involving Canada to date, this might permit it to maintain its current declaration indefinitely. However, if Canada does intend to retain this level of unilateral control over future ICJ cases, its current declaration is not the most effective way to do it. As it stands, precluding compulsory Court jurisdiction will require additional case-specific decisions made under significant time constraints. Making them will give rise to political costs each time, and any resulting jurisdictional restrictions would also highlight Canada’s own concerns about the legality of its related conduct. Although its current declaration also maintains Canada’s ability to initiate Optional Clause cases against other declarant states, it has never actually done so, and, in any event, this right will likely be substantially constrained by the reciprocal application of its own notification requirement.
Instead, Canada should now consider withdrawing its Optional Clause declaration altogether. This would afford it the same or greater control over future ICJ cases. However, no further steps would be required to bar Court jurisdiction in areas where it is unwilling to accept it. In particular, it would not remain subject to related initial claims premised on Optional Clause jurisdiction, let alone the ongoing, albeit limited, risk that successful legal challenges to its declaratory restrictions might allow them to proceed. Canada could still agree to ad hoc Court jurisdiction at any time, where the case-specific benefits of doing so are seen to outweigh the costs, as it did in Case Concerning Delimitation of the Maritime Boundary in the Gulf of Maine Area. It would also remain bound by various treaty compromissory clauses establishing compulsory ICJ jurisdiction over disputes involving subject-specific codified obligations that it has expressly accepted.Footnote 160
Joining the majority of UN member states without an Optional Clause declaration would therefore not signal a wholesale break from the Court. Among other things, this could temper any related public explanation, along with the ongoing cautionary tale of Alleged Violations of State Immunity. Regardless, the restrictions established in the 2023 Canadian Optional Clause declaration have already signalled the end of an era: as long as it maintains them, Canada is not making a meaningful advance commitment to accept compulsory ICJ jurisdiction in any related cases. Withdrawing its declaration would simply acknowledge this fact, allowing Canada, other states, and the ICJ to all move forward with greater certainty.
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