Abstract
The countermeasures doctrine has been developed through writings of modern and early legal scholars, decisions of international courts and tribunals, and the work of the International Law Commission. Under the countermeasures doctrine, a state is entitled to resort to proportionate unilateral measures against another state in response to the latter's violation of its international obligation, even if those measures would otherwise violate an international obligation of the former. The dissertation analyzes the countermeasures doctrine and under what circumstances countermeasures are an acceptable remedy under international law. To provide context, the dissertation reviews theories about sovereignty and how it allegedly limits the application of international law, and theories of international relations regarding cooperative or confrontational behavior of states.The countermeasures doctrine represents the fault lines between sovereign rights of states and the international system. For countermeasures to be an appropriate remedy, a rule of primary international obligation has to have been violated. In the context of international environmental obligations this requirement poses a particular problem because environmental obligations have often not developed into a clearly identifiable obligation of states. Nevertheless, in the absence of effective remedy for state which are effected by violations of international environmental obligations, and where cooperative measures have not been successful, resorting to countermeasures might be the only option sufficient to offset the consequences of an internationally wrongful act.Case studies are used to illustrate under what circumstances the countermeasures doctrine can be applied and used as a justification for enforcement of international environmental law.