Confiscatory measures against the property of an aggressor state: self-defence instead of sanctions?

Abstract The confiscation of an aggressor state’s property could significantly hinder its capacity to continue an unlawful armed attack, while the same assets could be used, directly or indirectly, to support the victim state’s exercise of self-defence. Such a measure may contravene various rules of international law, including state immunity from execution, diplomatic or consular inviolability, the principle of non-intervention, and protections afforded to foreign investments under international investment law. However, states may rely on circumstances precluding wrongfulness to justify such measures under the law of state responsibility. Against this background, the European Union’s ongoing freeze-or-seize dilemma concerns the possible legal justification for confiscating the Central Bank of Russia’s immobilized assets under the secondary rules of international law. This article explores and contends that self-defence, as a circumstance precluding wrongfulness reflected in Article 21 of the Articles on Responsibility of States for Internationally Wrongful Acts, could justify the confiscation of an aggressor state’s property, provided that the measure is lawfully and effectively implemented in the exercise of individual or collective self-defence in accordance with the primary rule. This conclusion may rest on two principal claims: confiscation is permissible under the primary rule governing self-defence either as a non-forcible exercise of self-defence or as an indirect use of force that contributes to halting and repelling the armed attack while respecting the limits of this inherent right under customary and conventional international law.