The international community’s response to Iran’s nuclear development program highlights the sometimes complex legal relationship between the UN system of collective security and the rights of states to take unilateral countermeasures under the law of state responsibility. It also raises a number of important questions about (a) the discretion afforded to states in the interpretation and implementation of Security Council resolutions, (b) the availability of countermeasures for the violation of multilateral obligations, and (c) the exclusivity of the Chapter VII framework for collective security.
This Article argues that, while the Security Council’s Iran sanctions resolutions do not grant discretionary authority to states to broaden the scope of the measures, states retain their rights under the law of state responsibility to take unilateral countermeasures in response to wrongful acts. Under the law of state responsibility, multilateral treaties like the Nuclear Non-Proliferation Treaty (NPT) are best understood as integrated agreements, such that in the event of non-compliance each State Party is entitled to treat itself as an “injured State” for the purposes of determining the availability of countermeasures. Moreover, quite apart from the question of whether the NPT is an integrated agreement, there is a substantial body of state practice supporting the right of states to take collective countermeasures in response to violations of multilateral obligations. The case for this entitlement is at its strongest where, as in the situation with Iran, the wrongful conduct has been determined by an international body with responsibility for monitoring and verifying compliance with the obligations in question. In such instances, the use of countermeasures in response to violations—far from undermining the international order—may serve to promote respect for the international rule of law.