It is a common misconception today that colonialism and territorial disputes belong to another age, that they are ‘ghosts of the past’ irrelevant to the modern world and international order. On the contrary, such affairs which can raise pertinent legal issues have never stopped being relevant and are of continuing interest to both practitioners and legal scholars. Territorial disputes and their international legal implications for States along with claims based on recognition, self-determination or sovereignty are still included in the docket of the International Court of Justice. More importantly, countries in Latin America and Africa that were occupied territories declared their independence and were recognized as post-colonial States only in the mid- or late 1900s, while the sovereignty of other territories, eg Gibraltar or Western Sahara, remains under dispute. In fact, such is the (legal) interest in territorial disputes and colonialism nowadays that even moot court competitions seem unable to resist the temptation of dedicating a notable proportion of their case study to colonialism, protectorates, mandates, territoriality or expropriation concerns in light of the post-World War I fall of the last empires, the dawn of independence and recognition of formerly colonized countries and protectorates.

This book written by Stephen Allen and Jamie Trinidad, both practising barristers and academics, serves as a strong reminder that these legal issues are still with us. However, the contribution of this book is not limited to reminding the reader of the importance of such issues; rather, it goes a step further to re-assess the circumstances and recent developments in the field of self-determination and recognition using as a vehicle the case of the Western Sahara question and its implications and complexities under international law.

In particular, the book analyses various aspects of the Western Sahara question, including the historical background, the involvement of the United Nations (UN), the legal dimensions (Chapter 1—Introduction, Chapter 2) and recent developments in UN practice (Chapter 4). It examines the conflicting claims of Morocco and the Sahrawi people regarding the sovereignty of Western Sahara and the applicability of the principle of self-determination (Chapter 2). The authors highlight Morocco's application of the ‘Hallstein doctrine’ to limit recognition of the Sahrawi Arab Democratic Republic (SADR), which was unilaterally declared by the Polisario Front in 1976 (Chapter 2). The book also explores the concept of recognition and the duty of non-recognition in international law, particularly in relation to Morocco's occupation of Western Sahara (Chapter 3). One of the key contributions of this book is its analysis of Morocco's efforts to advance its sovereignty claim over Western Sahara through various diplomatic means. The authors discuss how Morocco has utilized regional investment strategies, human rights initiatives and COVID diplomacy to promote its cause. Furthermore, the book delves into the implications of growing support for Morocco's territorial claim and the establishment of consulates in Western Sahara by sympathetic States (Chapter 5). It questions whether these actions amount to implied recognition of Morocco's sovereignty claim and explores the legal consequences of such recognition. In terms of contemporary international law in practice, the authors raise concerns about the erosion of peremptory norms, such as self-determination and territorial integrity, which are fundamental to the decolonization process. They suggest that the handling of the Western Sahara question could serve as an indicator of a potential shift away from a rules-based international order (Chapter 6—Conclusion).

This book differs from previous works or contributions on the topic of the Western Sahara question in several ways. First, it focuses on recent UN practice and developments in relation to Western Sahara, specifically analysing the approach of the Security Council, the General Assembly and its subsidiary committees. This allows for an assessment of how the UN has responded to events in the territory in recent years. Second, the book examines the notion of formalism and implied recognition by discussing the legal controversies surrounding the European Union/Morocco Trade and Fishing Agreements and their application in Western Sahara. It also explores the consequences of the duty of non-recognition, particularly in relation to persistent illegal situations and territorial claims. Third, it delves into recent State practice beyond the UN, exploring the legal ramifications of growing support among States for Morocco's autonomy plan and the establishment of consulates sympathetic to Morocco's sovereignty claim in Western Sahara. Fourth, the book considers the possibility of a future change in the status of Western Sahara that is opposed by the Sahrawi people and examines what this could mean for the future of international law, particularly the peremptory norms on self-determination and territorial integrity that underpin decolonization.

This interesting and important monograph by Allen and Trinidad also provides the reader with food for thought on the relevance of territorial disputes in general in the modern world, addressing the various issues across the volume. First, territorial disputes often revolve around the question of sovereignty and control over a particular piece of land or maritime area. States consider their territorial integrity and national security as paramount, and any encroachment upon or challenge to their territorial claims can lead to tensions and conflicts. These themes are addressed in Chapters 2, 4, 5 and 6. The issue of access to and exploitation of natural resources such as oil, gas, minerals or fisheries is another key concern, as control over these resources can have significant economic and strategic implications for the disputing parties. This competition for resources can escalate conflicts and hinder cooperation between States, as noted in Chapters 2, 3 and 4. Chapters 1, 4 and 6 consider ethnic or national identity as a driver for such disputes where different groups claim historical or cultural ties to a particular territory, often with related questions of self-determination and the desire for autonomy or independence. The humanitarian consequences of territorial disputes are addressed in Chapters 3 and 4. Displacement, human rights abuses, and restrictions on movement and access to basic services can result from such disputes, particularly for populations living in disputed areas, leading to humanitarian crises.

Two further issues relating to territorial disputes are addressed throughout the volume. The broader geopolitical implications are explored, given the potential impact upon regional power dynamics and alliances as States seek to expand their influence or counter the influence of rival powers by asserting territorial claims or supporting parties involved in disputes. Finally, territorial disputes raise important legal and normative questions regarding the interpretation and application of international law, including principles such as self-determination, territorial integrity and the prohibition of the use of force. Resolving these disputes requires adherence to established legal frameworks and international norms which are discussed throughout.

Overall, the book is a delight to read and provides a comprehensive analysis of the Western Sahara question, shedding light on the complexities of the dispute and its implications for contemporary international law. This work will be of interest to a wide pool of readers ranging from international law practitioners, academics and researchers in the field, legal and policy officers in international organizations, policymakers and foreign policy advisors, to any reader with a keen interest in international relations and diplomacy, international law, territorial disputes and conflicts, colonialism and self-determination.