Los asedios y el Derecho Internacional de los Conflictos Armados: nuevas perspectivas

Article Review

Andrés Miguel Cosialls Ubach, “Sieges and the Law of Armed Conflict: New Perspectives”

In Sieges and the Law of Armed Conflict: New Perspectives, Andrés Miguel Cosialls Ubach delivers a rigorous and timely doctrinal contribution to the contemporary understanding of siege warfare under International Humanitarian Law (IHL). Published in the CODESEL Bulletin (Vol. 1, No. 6, December 2025), the article addresses one of the most controversial and operationally recurrent practices in modern armed conflicts: the encirclement and isolation of populated areas as a method of warfare. 

The article’s principal strength lies in its deliberate departure from a reductive, binary debate—sieges as either lawful military operations or inherently unlawful practices. Instead, Cosialls Ubach advances a nuanced, effects-based analytical framework, firmly grounded in the normative structure of IHL. Drawing on classical military thought (from Sun Tzu to Vauban) and systematically confronting it with contemporary humanitarian norms, the author demonstrates that sieges are not prohibited per se, but are subject to increasingly restrictive legal constraints derived from the principles of distinction, proportionality, precautions in attack, and—most critically—the prohibition of starvation of civilians as a method of warfare under Article 54 of Additional Protocol I.

This analytical move aligns the article with the prevailing trajectory of IHL interpretation, which prioritises foreseeable and cumulative humanitarian effects over formal characterisations of military conduct.

One of the article’s most original contributions is its systematic typology of sieges, distinguishing between:

• Total or integral sieges,

• Partial or selective sieges,

• Dynamic or mobile sieges, and

• Digital and informational sieges.

This taxonomy is not merely descriptive. It functions as a legal diagnostic instrument, enabling the assessment of how different operational modalities generate distinct patterns of civilian harm and, consequently, different thresholds of illegality. The analysis of total sieges is particularly compelling, supporting the thesis that such operations tend toward what the author aptly characterises as “structural illegality”, insofar as their operational logic is inherently incompatible with sustained compliance with IHL obligations toward civilians.

Equally noteworthy is the treatment of partial and dynamic sieges, which the article identifies as legally more ambiguous and, paradoxically, more dangerous from an accountability perspective. Through engagement with ICTY jurisprudence—most notably Galić, Kupreškić, and Krstić—as well as recent ICC policy developments, Cosialls Ubach demonstrates how selective humanitarian access, conditional evacuations, and checkpoint-based restrictions may amount to indirect forms of coercion, forced displacement, or collective punishment.

The article offers an important warning for military legal advisers and commanders: formal compliance, such as the sporadic admission of humanitarian convoys, does not suffice where the overall effects of a siege result in sustained civilian deprivation.

The sections devoted to digital and informational sieges constitute one of the article’s most innovative elements. By extending the prohibition of starvation and the protection of indispensable civilian objects to cyber operations, telecommunications shutdowns, and interference with water and energy infrastructure, the author aligns his analysis with the effects-based logic increasingly endorsed by the ICRC and reflected in instruments such as the Tallinn Manual 2.0. The absence of kinetic force, the article persuasively argues, does not preclude the classification of such operations as unlawful sieges where their foreseeable consequences entail the collapse of essential civilian services.

Methodologically, the article combines doctrinal analysis, international jurisprudence, and empirical references to contemporary conflicts—including Sarajevo, Aleppo, Mariupol, Gaza, Tigray, and Yemen—in a manner that reinforces its operational relevance. The discussion of command responsibility under Article 28 of the Rome Statute is particularly persuasive, emphasising that sieges, by their prolonged and systemic nature, are especially conducive to establishing knowledge, foreseeability, and effective control on the part of senior commanders.

Sieges and the Law of Armed Conflict: New Perspectives stands out as a substantial and original contribution to contemporary IHL scholarship. Its central thesis—that the legality of siege warfare must be assessed primarily through its cumulative humanitarian effects—is both normatively demanding and doctrinally sound. The article will be of significant interest to international lawyers, military practitioners, humanitarian actors, and international criminal law specialists, offering a robust analytical framework for one of the most pressing challenges in the regulation of modern warfare.