16 November 2023

The Importance of State Party Pleadings in Treaty Interpretation

Adjudicators and interpreters can and should take into consideration written and oral pleadings submitted by States in international disputes in the process of treaty interpretation. State party pleadings should indeed not be seen as a suspect class of interpretative material. Moreover, when tribunals fail to give due accord and deference to such agreed interpretations, this may lead to reactions with respect to the international dispute settlement regime by some States. So argues Kendra Magraw in her recently defended thesis in International Law, which she discusses in more detail in this interview.

How did you come to choose your research topic?

I chose to write about my research topic because when I was undertaking my master in International Law at the Graduate Institute, I took Professor Pauwelyn’s Trade and Investment Law Clinic, in which our client was a State that requested an examination of the written pleadings from arbitral proceedings of one of its treaty partners to discover its positions on treaty interpretation contained therein. This led to the development of my thesis questions and my decision to do a doctorate on this topic.

Can you describe your thesis questions and the methodology you used to approach those questions?

My dissertation explored the possible roles in treaty interpretation of State party pleadings (which I have defined as States’ written and oral pleadings submitted in a dispute) under 11 possible conduits by which I hypothesised the content of State party pleadings (SPPs) on treaty interpretation might be considered by decision makers such as arbitrators or judges while interpreting treaties. Once I had selected these 11 conduits, I then went through them one-by-one with the aim of establishing that each one could function to bring the content of State party pleadings on treaty interpretation into the process of treaty interpretation.

My methodology included an extensive examination of relevant case law as well as the drafting history of the Vienna Convention on the Law of Treaties (and other relevant international agreements), as well as qualitative and quantitative analysis of the content of international investment agreements (such as bilateral investment treaties and free trade agreements).

What are your major findings?

My main conclusions include that State party pleadings (both written and oral) are a form of State practice that is not a suspect class of interpretative material, that they can and should be given weight in the interpretation of treaties, and that it is possible to do so under at least 11 different conduits that I hypothesised and ultimately established are capable of bringing the content of SPPs on matters of treaty interpretation into the interpretative process. My research indicated that State party pleadings are most likely to be considered under the Vienna Convention on the Law of Treaties with respect to Article 31(3)(a)-(b) and Article 32, although they might also be considered with respect to other related concepts such as authentic interpretations and statements against interest. 

What could be the practical implications of your thesis?

The examination of the role of SPPs in treaty interpretation is far from a theoretical exercise, especially in investor-State cases (or ISDS for short), where States have increasingly argued that the statements they make in their written or oral pleadings regarding matters of treaty interpretation have interpretive value that should – or must – be taken into a consideration by the tribunal. It is an issue that is often thought about carefully by legal counsel when drafting submissions and formulating legal strategies, and some countries have careful checks in place to ensure that their pleadings in this regard are consistent. 

What are you doing now?

I am specialised in amongst others dispute settlement and international arbitration, and anticipate that my career will continue to involve these areas in the future. I hope to continue exploring issues of practical importance such as the one my thesis addressed, as well as policy, procedural and substantive issues generally related to international law, international treaties and international dispute settlement.

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Kendra Magraw defended her PhD thesis in International Law in May 2023. Professor Zachary Douglas presided over the committee, which included Professor Joost Pauwelyn, Thesis Director, and Isabelle Van Damme, Partner, Van Bael & Bellis, Geneva.

Citation of the PhD thesis: 
Magraw, Kendra. “The Role of State Party Pleadings in Treaty Interpretation.” PhD thesis, Graduate Institute of International and Development Studies, Geneva, 2023.
The thesis is embargoed until June 2026. For access, please contact Kendra Magraw at

Interview by Nathalie Tanner, Research Office.
Banner image by Andrey_Popov/