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Subsequent behavior and treaty interpretation in public international law

Dr. Matar Hamid Al-Neyadi

23 August 2020

Interpretation of treaties is one of the most important means of implementing treaties and adhering to their provisions. At the same time, it is one of the issues that cause a difference between the states parties to the treaty, and thus leads to the suspension, suspension or modification of the implementation of the treaty, or some of its provisions, because interpretation is a “technical activity, with which specific rules or processes cannot be known”.

The reason for this is due to the fact that the treaty, or any other agreement, is nothing but a settlement between different positions, which pushes the negotiating parties in order to reach an agreement text, to try to use some kind of wording that is satisfactory to all the negotiating parties, regardless of About the fact that this formulation sometimes has more than one meaning, or it is imprecise or vague.

Since the implementation of the treaty is carried out by different parties and circles in the states parties, it is not necessary for these parties to understand the climate in which the treaty was drafted. Accordingly, these parties in each state party to the treaty begin to interpret the treaty in a manner that is consistent with its interests and orientations, at the time of implementation of the treaty, not at the time of its drafting.

This situation often causes disagreement among the treaty parties about their interpretation, and consequently a disagreement over the implementation of all or some of the treaty provisions. In addition, disagreements arise between the parties in some cases, regarding the suitability or necessity of implementing the provisions of a specific agreement that were drafted in a legal system that has become, at the present time, not present or has been replaced by a different legal system.

Because of the importance of the topic of treaty interpretation, the Vienna Convention on the Law of the Treaty of 1969 devoted Articles 31 and 32 to clarify the provisions relating to the interpretation of treaties, which represent what international custom has established in the field of treaty interpretation.

In this article, we will limit our discussion to the role of subsequent behavior in the treaty interpretation process, as the subsequent behavior of the parties to the treaty is strong evidence of a common understanding of the provisions of the treaty after its conclusion, and how to implement it.

This behavior cannot be ignored when interpreting the provisions of the vague treaty, giving it a different meaning to the subsequent behavior of its parties when they implement its provisions.

Subsequent behavior means: everything that is issued or signed by the parties to the treaty after its conclusion, and related to its subject matter, whether it is an act or a negation. This includes statements and opinions issued by officials, issuance and circulation of maps, issuance of legislation and daily practices of state institutions regarding a matter related to the subject of the agreement, including court rulings, silence about certain positions taken by another party to the treaty, or acceptance of the interpretation or method of implementation of one of the parties to the treaty for one Their items.

The subsequent behavior of the parties to the treaty, in this sense, is an aid to explain how they have understood and implemented the provisions of the treaty. In this role, it occupies an advanced position over other means of assisting interpretation, which may come to be considered the correct and accurate interpretation of the treaty.

In this regard, the International Court of Justice, in the context of its ruling in the conflict between Botswana and Namibia, over the sovereignty of the island of Kasikili / Sedudu in 1999, affirmed the position of the International Law Commission on the issue of subsequent behavior, and the practices of international justice with the help of subsequent conduct in the interpretation of treaties.

In order for the subsequent behavior to be considered in the interpretation process, it must be repeated in a consistent and recognized pattern, acceptable, even tacitly, by the parties to the treaty, and contemporary to the conclusion of the agreement.

If this behavior began a long time after the conclusion of the treaty, then it is not considered a contemporary understanding of its provisions, and therefore it has no consideration in the interpretation of the terms of the treaty, because it is not envisaged that it expresses the understanding of the parties to its provisions at the time of its conclusion. Rather, this behavior may have been affected by the change in policies or objectives of the treaty parties. But this does not mean that the subsequent conduct - which occurs by the parties to the treaty after a long period of time - has no legal value. Such behavior can be “used in establishing closure on one of the parties to the treaty,” if this behavior fulfills the conditions of closure, or it may be a means to prove that the agreement has been amended based on this behavior.

Adviser in public international law

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The treaty, or any other agreement, is nothing but a settlement between differing positions.