Open covenants of peace, openly arrived at, after that there shall be no private international understandings of any kind, but diplomacy shall proceed always frankly and in the public view.
Since 1919, when US President Woodrow Wilson issued this sincere, but hopelessly unworldly, appeal, diplomacy has continued to develop many new ways of doing business. Even when the subject matter is proper and lawful, diplomats know that it is not possible for all international deals to be embodied in treaties, whether or not they are on trivial or important matters. Yet the deal needs to be formalised on paper in some way. Hence, the relentless rise of the MOU (or political commitment); that instrument, which, although concluded between states, is not legally binding.
Such non-legally binding instruments have also been variously described as ‘political agreements’, ‘gentlemen's agreements’, ‘non-legally binding agreements’, ‘non-binding agreements’, ‘de facto agreements’, ‘non-legal agreements’, etc. Diplomats – who are well aware of such instruments – generally refer to them, and not only in English, as ‘memorandums of understanding’ or ‘MOUs’. But calling an instrument a memorandum of understanding does not, in itself, determine its status, since – most confusingly – some treaties are also called memorandum of understanding. MOUs (properly so-called) operate as political commitments, and may be distinguished from treaties according to the International Law Commission (ILC) because they are not agreements governed by international law. An MOU may, however, still loosely be referred to as an ‘agreement’, even though it represents a deal between states, there is no intention that it should be legally binding in international law.