1. I, the undersigned, Professor at the University Paris Ouest, Nanterre-La Défense, former Chairman of the International Law Commission of the United Nations and Associate Member of the Institut de Droit International, have been asked to write a short expert opinion1 on the following question:

1. Does a dispute, within the usual meaning of the word in international law, presupposes in all cases a "positive opposition"? If yes, what is the precise meaning of this expression?

2. Can a dispute concerning the interpretation of a treaty be submitted to an international tribunal, absent any dispute on the application of the treaty? In particular, when a compromissory clause allows for arbitration of disputes “concerning the interpretation or application” of a treaty, may a tribunal exercise jurisdiction in circumstances where the dispute at issue concerns only the interpretation of the treaty and does not include an allegation that the respondent State breached the treaty?

3. The US are under an obligation to enter into consultation on the interpretation of the BIT (under Article V). If they refuse to do so, is there a dispute between the Parties? Can such a dispute be submitted to an interstate arbitration in application of Article VII?

4. In the circumstances presented here, is the Tribunal warranted in finding that a dispute exists between Ecuador and the United States regarding the interpretation of Article II (7) of the Treaty? In particular, does a dispute concerning the interpretation of a treaty satisfy the requirement of concreteness under international law notwithstanding the absence of an allegation that the treaty was breached?

In addition, I have been invited to express my views on any issues raised by Professor Reisman and Professor Tomuschat in their legal opinions joined to the Defendant’s Memorial on Objections to Jurisdiction, that I think should be addressed.