International treaties are one of the most important means of interaction, both between states and with international organizations. Through treaties, various political, legal, military, commercial, judicial and other international relations are enhanced and organized. Most of the provisions of the 1969 Vienna Convention on the Law of Treaties reflect established international practice in this regard. However, states’ actions sometimes add new rules and dealings to the provisions of the Law of Treaties.

A treaty is defined as “a written international agreement, governed by international law, between two or more states, whether contained in one document or two or more interrelated instruments, regardless of their particular designation.” This definition demonstrates the conditions or elements that must exist in a particular document in order for it to be described as a “treaty” or “convention,” which dictate whether the provisions of the Vienna Convention on the Law of Treaties can be applied thereon. In spite of the clarity of those conditions, the actions of states, alongside rapid technological development, have produced certain types of documents that may be difficult to classify as treaties at first glance.

In this lecture, we shall discuss the conditions that must be met by a document that qualify it to be considered a treaty, and the developments resulting from the practices of states in this context. We will also discuss memoranda of understanding, and whether they are considered international agreements that entail legal obligations on their parties, and the difference between memoranda of understanding and international conventions. This will be followed by a discussion of verbal agreements and official statements. The lecture will conclude with an exploration of “soft law” – or law in the making – and the pros and cons of its use.