ABSTRACT
It is sometimes argued that a state is under a duty in customary international law to consult another state if a decision that it is about to take will affect that state.3 However, the concept of ‘consultation’ should be distinguished between cases of ‘prior notification’ and those cases of ‘prior consent’. In the former instance the affected state is given an opportunity to comment and such a process may properly be called consultation. However, in the latter instance state A is seeking to obtain the consent of state B before it takes a decision. Having regard to the basic principle of the sovereignty of states international law will be slow to assume that an obligation of prior consent arises4 although it may in cases of joint sovereignty over territory or where there is a provision for joint decision taking arising under a treaty. It may be that an agreement provides for a measure of consultation and examples are afforded by the Antarctic Treaty 1959 or by the 1990 Interim Reciprocal Information and Consultation System established to defuse tension and to regulate the movement of British and Argentine forces in the South Western Atlantic. It is doubtful whether there is a general duty to negotiate (which includes consultation) arising in customary international law, but it is common to find such duties arising by treaty.
