 Treaty negotiations are a great subject for historians and scholars of international relations. This is because treaties are often important instruments of international polities. Well, just think for instance at certain peace treaties that have had a lasting influence on human history. If treaty negotiations can be fascinating from an historical or political perspective, they are however rarely a subject of concern for international lawyers. And indeed, international law does not provide many rules about how to negotiate a treaty. And this is because in order for negotiations to be successful, states should be free to set up the negotiating framework, the agenda and the process as they wish. Of course, those issues may require prior consultations and negotiations. States must first agree that it is a good idea to negotiate a treaty about a specific topic and then they must agree on the way forward, on the negotiating process itself. Where will it take place, what will be the pace of negotiations, how proposals will be exchanged and discussed etc. But all this is very much left unregulated by international law simply because it is impossible to set up in advance clear rules on all those issues. Each negotiation is different and must therefore be conducted differently without being limited by predetermined rules. Having rules on all aspects of negotiations could indeed be counterproductive as it could slow down, discourage or derail the negotiations. So there are very few rules of international law applicable to every single treaty negotiation. However, and because it would be a waste of time to negotiate a treaty with persons who are not entitled to speak and to bargain on behalf of the future contracting parties, one of the very few rules relating to treaty negotiations stem from the long-established practice according to which persons sitting at the negotiating table must produce appropriate full powers. Under article 2 paragraph 1c of the Vienna Convention, full powers are defined as a document emanating from the competent authority of a state, designating a person or persons to represent the state for negotiating, adopting or authenticating the text of a treaty for expressing the consent of the state to be bound by a treaty or for accomplishing any other act with respect to a treaty. The practice relating to full powers has been codified by article 7 of the Vienna Convention on the Law of Treaties and you will find its text in the documents of the course and a similar provision exists in the 1986 Vienna Convention on Treaties by International Organisations. Full powers are usually established by a letter signed by the Minister of Foreign Affairs of the State or the Secretary General of the Organization concerned and in all time of global communications the requirement of full powers may seem a bit outdated and there is not much to say about it as it rarely raises problems. However it is interesting to note that paragraph 2 of article 7 establishes presumptions of full powers. The persons that are specifically listed in paragraph 2 that is heads of states, heads of governments and ministers of foreign affairs, heads of diplomatic missions, representatives, accredited to international conferences or organizations, all those people are presumed to have full powers for the purpose of the negotiation and the conclusion of the treaty so much that they do not need to produce any document establishing that they have full powers. And it would indeed be quite absurd to see for instance the Minister of Foreign Affairs of the State writing to himself or to herself a letter of full powers. In the case between Cameroon and Nigeria the question arose as to whether a joint declaration made by the two heads of states amounted to an international agreement tracing part of the maritime border between the two states. And the court considered that the declaration amounted to such a treaty and it rejected Nigeria's argument according to which article 7 paragraph 2 of the Vienna Convention would be solely concerned with the way in which a person's function as a state representative is established. Whether the court considered that the presumptions of article 7 paragraph 2 I quote, deal with the extent of the person's power when exercising that representative function end of quote. Hence the presumptions are substantive and not only formal. They relate to the extent of the powers to represent the state not only to the presumptive way by which such representation is established.