International Reactions to the Crimea Annexation under the Law of State Responsibility: "Collective Countermeasures" and Beyond?

The paper intends to frame the 2014 Russian annexation of Crimea within the regime of the legal consequences of serious breaches of erga omnes (and ius cogens) obligations, as set out in the UN International Law Commission’s 2001 Draft Articles on State Responsibility. It is submitted that the restrictive measures adopted against Russia by some Western States and the European Union may substantiate an egregious case for third party, or “collective”, countermeasures taken by states not directly affected by the violation of erga omnes obligations. In this vein, the Crimean case can contribute to the clarification of one of the topical issues left unanswered under Art. 54 of the ILC Draft, concerning the admissibility of “collective countermeasures” in current international law. If, from a substantive point of view, the right of non-directly-injured States to take countermeasures can be affirmed after the Crimean case, uncertainties still remain as to the procedural aspects of its implementation. In particular, the precedent of Crimea tells very little as to the way of coordinating the different reactions adopted by third parties involved, thereby confirming that decentralisation still dominates the law of State responsibility and the regime of collective responses to violations of erga omnes obligations in international law