International Agreement

A treaty, the typical instrument of international relations, is defined by the 1969 Vienna Convention on the Law of Treaties as an “agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation. Contractual treaties are treaties by which the parties agree to exchange pieces of territory or settle a dispute or claims—that is, by which they deal with a particular kind of business. Lawmaking treaties, which have grown tremendously in number and significance since World War II, are instruments in which the parties formulate principles or detailed rules for their future conduct.”

Treaties, however, are not the only instruments by which international agreements are concluded. There are single instruments that lack the formality of a treaty called agreed minute, memorandum of agreement, or modus vivendi; there are formal single instruments called convention, agreement, protocol, declaration, charter, covenant, pact, statute, final act, general act, and concordat (the usual designation for accords with the Holy); finally there are less formal agreements consisting of two or more instruments, such as “exchange of notes” or “exchange of letters.”

In the absence of an international legislature, the multilateral treaty is the chosen instrument for adapting international law to changing circumstances brought about by rapid technological developments and the ever-growing interdependence of nations.

The Vienna Convention on the Law of Treaties contains a compromissory clause (whereby participants agree to submit disputes to arbitration or the International Court of Justice) for certain types of disputes and a procedure of conciliation for others. The resistance of states to compulsory arbitration or adjudication is indicative of their limited commitment to universal integration through the rule of law. In this respect the European Economic Community is an exception, providing as it does for the compulsory settlement of disputes arising under the three constituent treaties by the Court of Justice, which is open even to individuals. It may be noted that Western Europe was the cradle of nationalism and the doctrine of the sovereignty of states. Now it may have become the cradle of supranational integration.