In recent years, the (modern) law of self-determination has attained increased attention across most different realms of international legal scholarship and yielded scores of insightful contributions. One aspect commonly omitted in this respect, however, has been the sometimes-delicate relationship between self-determination and territorial integrity, particularly in the context of decolonization – a phenomenon recently revisited by the International Court of Justice in its Advisory Opinion on the Chagos Archipelago.Footnote ¹

Originally conceived as a PhD thesis at Cambridge University, in the present book, Jamie Trinidad undertakes a persuasive attempt to consolidate this widely neglected pillar of the law of self-determination. Trinidad essentially argues that – given that the modern scholarship on self-determination has mainly engaged with confronting contemporary challenges in international law rather than accounting for historical injustices – a series of colonial cases that could give rise to self-determination (measures) have, in fact, remained unsolved, thereby not only causing ramifications for contemporary international politics, but likewise bearing far-reaching implications for the overall normative framework governing the modern law of self-determination. Methodologically grounded on a clearly positivist footing, Trinidad thus embarks on a comprehensive analysis of both international practice and legal doctrine with regard to Non-Self-Governing Territories (NSGTs) under Chapter XI of the United Nations Charter – in particular to those ‘disputed colonial territories where external self-determination has been denied or qualified’Footnote ² – and focuses on a selection of anomalous decolonization cases in ‘which the political interests of States … come to bear not only on the scope of colonial self-determination but also on its application, especially when decolonization takes place under the shadow of an irredentist claim over the territory in question’.Footnote ³

Subdivided into five chapters, the book commences by exposing the core characteristics and dimensions of the law of self-determination in the post-Second World War era. To this effect, Trinidad links his overall narrative to the United Nations General Assembly and its role in drafting Resolution 1514 (XV),Footnote ⁴ the latter ‘epitomiz[ing] an international concern for managing two broad imperatives, which often exist in a state of uneasy tension: the interest in preserving international order on the one hand, and the interest in promoting justice on the other hand’.Footnote ⁵ It is this delicate balancing of order and justice-based imperatives, Trinidad argues, that essentially lies at the epicentre of the modern law of self-determination and may therefore be characterized as ‘the product of a “redefinition and synthesis” of the principles of territorial integrity and self-determination’.Footnote ⁶

Chapter Two, entitled ‘Territorial Integrity and the Limits of Self-Determination’, subsequently focuses on the Colonial Declaration and its overall importance for the evolution of the modern law of self-determination. In particular, Trinidad stresses the pivotal impact of paragraph 6 and its underlying principle of territorial integrity, stipulating ‘that “[a]ny attempt” aimed at the partial or total disruption of the national unity and the territorial integrity of a country is incompatible with the purposes and principles of the Charter of the United Nations’.Footnote ⁷ Trinidad hence utilizes paragraph 6 as a kaleidoscope for his analysis by arguing that emancipation from colonial rule might be conceived of as a controlled exercise in facilitating international justice, whereas eventual disruptive effects could be mitigated by ensuring that emancipatory change is effectively underpinned by a general concern for international order. In so doing, Trinidad carefully carves out the conflicting interpretations of paragraph 6 that have featured in the literature and moreover engages in a close examination of the Western Sahara Advisory Opinion,Footnote ⁸ thus particularly focusing on paragraph 6’s ambiguity regarding territorial integrity as a possible limitation to self-determination in the decolonization process. In order to further conceptualize paragraph 6, Trinidad also introduces the notion of irredentist claims to NSGTs, arguing that paragraph 6 might ‘be invoked to justify the subversion of present-day territorial sovereignty over a Non-Self-Governing Territory in favour of a “reintegration” claim by a neighbouring State, grounded on the experience of pre-colonial ties between the irredentist State and the Non-Self-Governing Territory in question’.Footnote ⁹ Trinidad further underlines the importance of paragraph 6 for the subsequent development of the law of self-determination by closely engaging with the notion of pre-existing ‘legal ties’Footnote ¹⁰ of territorial sovereignty as discussed by the ICJ in Western Sahara, in which the Court explicated that the existence of a previously existing link between a claimant state and a NSGT would not, as such, affect the application of the Colonial Declaration, i.e., the ‘principle of self-determination through the free and genuine expression of the will of the peoples of the Territory.Footnote ¹¹ Analysing the ICJ’s remarks on the notion of legal ties with regard to paragraph 6, Trinidad exposes an inherent ambiguity in the Advisory Opinion by casting doubt on the generality of its original proposition, i.e., that the right to self-determination is conceptually broad in scope: while the Court thus approved of its earlier assessment in the Namibia opinionFootnote ¹² – namely that the principle of self-determination would apply to all Chapter XI NSGTs – at the same time, it implicitly questioned and restricted this generality, hence creating what Trinidad correctly identifies to be a lifeline argument for states with certain historical, geographical and/or ethnicity-based claims to NSGTs, regardless of whether ties of territorial sovereignty previously existed between the claimant State and the NSGT in question.Footnote ¹³

In Chapter Three on ‘Territorial Integrity, Irredentist Claims and the Identification of Self-Determination Units in Practice’, Trinidad attends to a series of disputed colonial territories that have been identified as anomalous in the literature and ought to be conceptualized in accordance with a conventional rather than an irredentist interpretation of paragraph 6. To this effect, Trinidad differentiates between three distinct subtypes: firstly, disputes arising from the generally prohibited fragmentation of NSGTs by the administering power prior to or during the course of decolonization (including Mayotte, Scattered Islands, and Chagos Islands) as well as a series of exceptional departures from the territorial integrity principle that have been met with outright approval or tacit acceptance by the international community, thereby constituting a departure from the uti possidetis principle (including British Cameroons, Ruanda-Urundi, the Pacific Islands Trust Territories, Gilbert and Ellice Islands Colony as well as Cocos (Keeling) Islands, and Christmas Island). Secondly, cases characterized by an irredentist claim based on ties of territorial sovereignty as evinced by treaty (including the Panama Canal Zone, Hong Kong New Territories, Macau, and Gibraltar) as well as, thirdly, the special case of the Falklands/Malvinas Island as a dispute over title not based on historical grounds. While acknowledging that some of these cases comprise anomalous characteristics, Trinidad maintains that they ought to be conceptualized according to a conventional understanding of territorial integrity limiting the scope of self-determination in colonial contexts. While one could question whether the case selection and classification proposed here is sufficiently selective, Trinidad’s analysis substantially adds towards a more nuanced understanding of the actual scope of self-determination, not least as it convincingly demonstrates how the territorial definition of ‘people’ has prevailed in the context of decolonization: accordingly, where an irredentist claimant can establish that it has retained territorial sovereignty over a colonially administered territory, the wishes of the affected population will not trump the principle of territorial sovereignty, since – in those cases – the affected population would not constitute a ‘people’ capable of determining the destiny of the territory in question.

Chapter Four subsequently questions whether there exists ‘a “Colonial Enclaves” Exception to the Self-Determination Rule’, thereby turning towards ‘the untidy edges of decolonization practice and doctrine’.Footnote ¹⁴ Here, Trinidad convincingly attempts to conceptualize those cases that cannot be rationalized according to a conventional understanding of territorial integrity and self-determination, but instead refer to claims for the restoration of some form of pre-colonial status quo. This notion especially pertains to the ‘colonial enclaves doctrine’,Footnote ¹⁵ which Trinidad thoroughly exposes by engaging in a comprehensive literature review, thereby also elucidating the doctrine’s material foundation within the law of decolonization. After examining various exemplary cases putatively falling into the remit of the colonial enclaves doctrine and arguing that these cases may not be grounded on a coherent doctrine of exception, but rather on an irredentist interpretation of paragraph 6, Trinidad designates the French territorial possessions in India, São João Baptista de Ajudá, the Portuguese Dependencies in India, Ifni, Gibraltar, and Walvis Bay as notable anomalous deviations from the self-determination rule. Also, Trinidad highlights Belize and East Timor as cases in which disputed enclave-like territories have effectively realized self-determination and moreover contrasts these findings with the case of Spain’s remaining enclaves in Africa (Ceuta and Melilla). The Chapter finishes by contending that deviations from the self-determination rule in disputed enclave-like territories may not be explained by referring to a coherent legal doctrine of exception, but ultimately depend on the ‘role played by discretionary policy judgments in shaping decolonization outcomes’,Footnote ¹⁶ including the eventual application of what Trinidad rightly characterizes as palliative self-determination measures.

Trinidad concludes his opus by arguing that ‘within the normative framework governing the decolonization process, the principles of territorial integrity and self-determination can be viewed as two sides of the same coin’:Footnote ¹⁷ while he, thus, remains sceptical of a putative doctrine of exception as a means of rationalizing the non-realization of self-determination in some of the discussed cases and acknowledges that other cases have been explained in accordance with a conventional interpretation of the territorial integrity principle, Trinidad concedes that a small number of cases could not be persuasively accounted for within the presented normative framework, especially since the analysis conducted in Chapter Four found no clear evidence of a coherent doctrine of exception from the self-determination rule. Trinidad therefore suggests that the distinct treatment of territories such as Goa or Gibraltar may best be explained on political, rather than principled legal grounds: while this finding may seem unsatisfactory at first sight – particularly as it inevitably undermines the establishment of a truly coherent normative framework governing self-determination in the decolonization context – it also echoes a realist and pragmatical appraisal of contemporary political circumstances.

Jamie Trinidad has written a meticulously researched monograph that comprehensively elucidates on a widely neglected topic, which remains highly relevant for the stability of contemporary international relations. The book is fluently written and benefits from an extensive engagement with both relevant literature and case law. While a second edition might warrant some minor revisions and corrections, the book’s overall significance – including for neighbouring disciplines such as international relations or cultural geography – is hardly neglectable: the inherently interdisciplinary character of the subject-matter is visible throughout the book and its treatment lastingly benefits from the author’s academic background in both international law and international relations, hence enabling him to carefully manoeuvre along the sometimes-thin line between legal doctrine and political realities. From a methodological angle, however, the book might have benefitted from a more articulated analytical framework for identifying, grouping, and comparing the cases under examination.

Notwithstanding these criticisms, Trinidad has written a highly recommendable book that provides a comprehensive account of the law of self-determination in the context of disputed colonial territories and therefore should find its regular spot on the desk of every (legal) scholar working on the subject-matter.