1. Treaty interpretation

2. Importance of Articles 31-33 of the VCLT
”[T]he Convention applies only to treaties which are conluded by States after the entry into force of the present Convention with regard to such States”.
The second branch of the doctrine of intertemporal law
Guinea – Guinea-Bissau Maritime Delimitation
Treaty concluded by France and Portugal on 12 May 1886

3. Means of interpretation
Conventional language (”the ordinary meaning”)
Context
Object and purpose
Supplementary means of interpretation, including:
Preparatory work
The circumstances of the conclusion of a treaty

4. Guinea – Guinea-Bissau Maritime Delimitation

5. Guinea – Guinea-Bissau Maritime Delimitation

6. Guinea – Guinea-Bissau Maritime Delimitation

7. Guinea – Guinea-Bissau Maritime Delimitation

8. Guinea – Guinea-Bissau Maritime Delimitation

9. Hierarchy Article 32: Article 31(4):
“Recourse may be had to supplementary means of interpretation, including the preparatory work of the treaty and the circumstances of its conclusion, in order to confirm the meaning resulting from the application of article 31, or to determine the meaning when the interpretation according to article 31: (a) leaves the meaning ambiguous or obscure; or (b) leads to a result which is manifestly absurd or unreasonable.”
Article 31(4):
“A special meaning shall be given to a term if it is established that the parties so intended.”

10. The context of operation
Treaty interpretation can be explained in a context of discovery
Treaty interpretation can be explained in a context of justification
What is the role of the law laid down in Arts for each of these explanations?

11. The clear meaning The plain meaning doctrine (E de Vattel):
A process of interpretation shall be initiated only when the meaning of a treaty is unclear
A process of interpretation shall be concluded only when clarity has been attained.
There are other ways than interpretation to understand a treaty
Article 33(4):
“Except where a particular text prevails in accordance with paragraph 1, when a comparison of the authentic texts discloses a difference of meaning which the application of articles 31 and 32 does not remove, the meaning which best reconciles the texts, having regard to the object and purpose of the treaty, shall be adopted.”

12. The Schwebel/Mortenson fallacy
”How can you know whether a treaty is clear or not before you have subjected it to interpretation?”
”How can you know whether preparatory work will confirm the clear meaning that you have already adopted as correct, or whether it will prove you wrong?”

13. Party intention
What is this thing called ”the intention of the treaty parties”?
What do you do when an intention is lacking?
How do the means of interpretation relate to the idea of party intention?

14. Klabbers v. Linderfalk Is interpretation art or science?
”No understanding of a treaty provision can be rationally explained by reference to the law laid down in Articles 31-33”
Is this suggestion consistent with the terms of Articles 31-33?

15. Are there any rules of interpretation proper?