Introductory Remarks Marija Ozolins

We are so lucky to have a fantastic panel with us today. I will introduce them briefly, but I encourage you to read their full bios because the achievements of our panelists are far too many for me to list today.

I will start with Luciana Ricart, my colleague at Curtis, Mallet-Prevost, Colt & Mosle. She is a partner in our London office, and she represents and advises states in investment arbitration and public international disputes.

Next, we have Sean Murphy. He is the Manatt/Ahn Professor of International Law at George Washington University here in Washington, D.C. and he has taught there since 1998. His previous positions, among others, include legal counselor to the U.S. Embassy in The Hague, where he provided support to the International Criminal Tribunal for the former Yugoslavia. He was also a U.S. agent to the Iran-U.S. Claims Tribunal, and he has served as arbitrator and counsel in many of the most fascinating international arbitration cases.

Then we have Joan Donoghue, a visiting Professor of Law at UC Berkeley, and she is an Arbitrator Member of Twenty Essex Chambers. She was a judge at the International Court of Justice from 2010 to 2024, and she was president of the Court from 2021 to 2024. And this year, from 2025 to 2026, she will be the Arthur Goodheart visiting professor in Legal Science at Cambridge University.

Here next to me, we have Samaa Haridi. She is a partner at King and Spalding, and serves as counsel and sits as arbitrator in international commercial and investment disputes.

And last but not least, we have our moderator Amir Farhadi. He is a senior associate in the International Litigation and Arbitration Department at Foley Hoag, where he acts as counsel to states in advisory and contentious proceedings before the ICJ and in inter-state and investor state arbitrations, and he was a former judicial fellow of the ICJ.

Remarks by Amir Farhadi

Thank you so much, Marija, for the kind introduction. Thank you all for being here today and for this great turnout. We are really honored. I want to echo the thanks to everyone at ASIL, especially Taylor Kilpatrick, everyone at the International Bar Association (IBA) and, of course, our panelists who accepted to participate in this panel, which was arranged only a few weeks ago. And that is because this is the first ever joint IBA-ASIL panel here at the Annual Meeting. We hope it will be the first of many more in the future.

The topic of today’s panel is “Rulemaking in the Practice of International Law.” This felt to us a very natural way to capture the intersection of the two organizations: ASIL of course, is dedicated to academics and practitioners of public international law. For its part, the IBA Arbitration Committee is devoted to practitioners of investment and commercial arbitration.

But these fields, of course, have a lot of overlap and intersect in many ways. In fact, we spent yesterday at the very interesting ITA-ASIL conference discussing the theme of the impact of public international law on arbitration. And the buzzword of the morning, I think it is fair to say, was cross-pollination. Today we are going discuss a little bit more about this cross-pollination or spillover between these two fields.

I would put it to you that part of the reason why this cross-pollination occurs is because of practitioners like those on this panel—and those in the room—who have a foot in both worlds. So in looking at this phenomenon, we specifically want to think about the way in which practitioners influence the elaboration and creation of rules that are applied today in practice.

Of course, the most obvious examples of rules—this being an IBA-sponsored event—are the IBA Rules on the Taking of Evidence, and its Guidelines on Conflict of Interest. I want to stress that these are, yes, procedural tools, but they also go to fundamental issues of due process and of the right to be heard, such as the right to appear before an independent and impartial tribunal. But the IBA is not alone in this rulemaking function. Other organizations, arbitral institutions, and the International Law Association (ILA) do this kind of work.

One question that arises, and I hope it is something we are going to touch upon, is how do these exercises driven by practitioners stack up against what we know as the traditional sources of international law set out in Article 38 of the International Court of Justice (ICJ) statute? Are the IBA Rules a codification of customary international law? I do not think so. Are they a reflection of general principles of law? Maybe some of them. Are they teachings of the most qualified publicists? Maybe—it depends.

No matter how we try to classify them, these rules are applied today, whether we like it or not. And I do not just mean in investment arbitration. Let me give you an example. There are two interstate arbitrations pending between the Republic of Armenia and the Republic of Azerbaijan: one was brought under the Energy Charter Treaty, and the other under the Bern Convention on the Conservation of European Wildlife and Natural Habitats. You can find the procedural rules of these two cases on the Permanent Court of Arbitration (PCA) website. Both sets of rules provide that the respective tribunal shall be guided by the IBA Rules on the Taking of Evidence.Footnote ¹ In other words, two sovereign states agreed to apply the IBA Rules as between them in interstate disputes. That decision was endorsed by six very eminent arbitrators, including former ICJ Judges, ILC members, and the president of the Iran-U.S. Claims Tribunal. I think that is quite something. It is maybe not exactly what the drafters of the Permanent Court of International Justice (PCIJ) Statute had in mind in 1920, but it is where we are today.

Before we dive into some questions, we have a very short video of some remarks from Chiann Bao, who is the co-chair of the IBA Arbitration Committee and an arbitrator based primarily in Singapore.

Remarks by Chiann Bao

It is a great pleasure to have the opportunity to offer a few welcome remarks to open up this joint panel between ASIL and the IBA. The two have similar core missions. For ASIL, it is to promote the establishment and maintenance of international relations on the basis of law and justice. The IBA, through its Arbitration Committee, strives for the same, as it was born out of the conviction that it could contribute to the global civility and peace through the promotion and protection of the rule of law. These words ring true through all aspects of the work of the IBA Arbitration Committee. We comprise of over 3,000 members from all over the world. As a bar association, we are open to all lawyers. And indeed, in my experience at the IBA, I see the great potential of this Committee with its inherent global reach, but also with the good foresight of those before me to use this platform to harmonize and standardize best practices.

Through this, we ensure that we have a common language for some of the most critical features of our practice, including the well-known Conflict of Interest Guidelines, as well as the Rules on the Taking of Evidence. In this way, the IBA facilitates the rule-based system of dispensing justice, and more broadly in line with ASIL’s mission, opens up the lines of communication between lawyers from around the world to ensure that relations amongst the international bar remain free from influence and persuasion. Indeed, the Arbitration Committee in general aims to democratize our system, making available best practices of international arbitration to all of those who are involved through the work of our task forces. We survey the need for harmonizing certain practices and then carry out global initiatives to set standards and guidelines to ensure the legitimacy of our work. We include members from all over the world to participate in the dialogue as well as academics, judges, and end users.

For example, we currently have several ongoing task forces, including one on AI, res judicata, as well as privilege, initiated during Samaa Haridi’s tenure as co-chair. Our project studying the impact of ethnic diversity on the role of the arbitrator has just launched its report this week. In this year, we are also launching two new projects. The first one is a study on nationality and its role as a proxy for independence and impartiality of an arbitrator, and the second one is to review the need to revise the 1987 ethics rules and explore how to concretize global standards on ethics for arbitrators. All of these projects involve the participation of practitioners to be sure, but also as I mentioned, end users, judges, and academics as well. Indeed, the whole ecosystem of the international arbitration community. As humans, we have the inherent tendency to create categories and draw lines to differentiate each other. Recognizing this, we believe that it is much more important that we have rulemaking bodies to minimize the impact of these lines and open up the dialogue to all. And as custodians to the legitimacy of international arbitration, we have the opportunity to participate in the dialogue. Thank you very much and enjoy the fruitful discussions ahead.

Remarks by Samaa Haridi

It is a pleasure and honor to join this esteemed panel today. I am going to take a slightly deeper dive to talk about how these soft laws are developed. I think it is fair to say that the International Bar Association is one of the most active organizations when it comes to creating international arbitration soft law instruments. Perhaps the most famous one is the IBA Rules on the Taking of Evidence. Very close to it are the IBA Guidelines of Conflicts of Interest, which were amended in 2024, and then the less used IBA Guidelines on Party Representation, which are currently the topic of some discussion regarding whether or not they should be updated.

In terms of process, I will use the IBA Rules on the Taking of Evidence as my illustration point, because I was closely involved at the time the amended rules came into force. You already know that the first iteration of these rules came out in 1999, and when they were put together, which precedes my time on the committee. The idea was to really try to bridge the gap between common and civil law systems and to assist parties and arbitral tribunals in all matters related to evidence and in the conduct of the proceeding and the procedural aspects of the arbitration. Revised versions were published in 2010, and then typically the IBA Arbitration Committee—every ten years on the anniversary of one of its soft law instruments—will look at whether or not that instrument should be amended.

In June of 2015, the Arbitration Committee organized the Guidelines and Rules Subcommittee, and that Subcommittee launched a worldwide survey on the use of these soft law instruments. This culminated in September of 2016 with a report on the reception of the IBA arbitration soft law products. Over 800 responses were received, and the majority of the people who responded actually said that they were satisfied with those soft laws as enacted. At that time less than 10 percent expressed the view that any of these soft laws should be amended. Notwithstanding that response, the Task Force and the Subcommittee decided to form together a working group to look at the rules of evidence specifically and whether they should be amended.

These groups offered a lot of comments. And then a period of public comments was opened in which a revised draft of the rules was proposed, and comments were solicited from academics, practitioners, arbitral organizations, which resulted in substantial input being provided. So all of that then resulted in the amendments that we know now exist and came into effect in December of 2020 when the new version of the IBA Rules on the Taking of Evidence were adopted.

That is, in a nutshell, the process. That is also the process that I know started when I was still on the Committee, and then resulted in the revisions to the Guidelines on Conflict of Interest which came into effect in 2024. The idea is to gather as much public commentary as possible and to seek a process where all views are heard, and of course implemented to the extent possible in these amendments.

Remarks by Sean Murphy

Thanks as well for the invitation to be here. It is really a great pleasure. It may be interesting to note that the IBA, I believe, was founded the same year that the ILC was established: 1947, although the ILC only met for the first time in 1949. But it is interesting that, in this post-war period, the idea of promoting global peace, security, stability, and rule of law was emerging in different ways, including through the codification of rules.

The ILC is a very different institution than the IBA. The ILC is comprised of thirty-four members elected by the UN General Assembly, as compared with some 80,000 members of the IBA. Like the IBA, the ILC has a lot of practitioners; they are often government practitioners, but it is not dominantly academics. So, you get a pretty good breadth of experience at the ILC. I have been an academic for some twenty-five years, but I was a government practitioner for eleven years before that, and in both roles was doing a fair amount of litigation and arbitration. So, I think on the ILC, you will get people with a diversity of experience, as you do at the IBA.

The working methods are quite different. The ILC typically appoints someone as a special rapporteur. It can convene study groups or working groups, but often it is a special rapporteur who is tasked over a period of years to develop multiple reports that will be debated in Geneva.

Proposed rules go into a drafting committee and will then be finalized through the work of the commission as a whole. In conjunction with those rules are commentary explaining what the rules are. Ultimately, the end product could be a treaty, like the 1969 Vienna Convention on the Law of Treaties, or it could just be draft articles, like the 2001 Articles on State Responsibility. The ILC also produces “conclusions” and “principles; for example, Sir Michael Wood was special rapporteur for the ILC’s 2018 conclusions on identification of customary international law. So there is some amount of what one might regard as soft law popping out of the ILC as well, but also hard law in the form of draft articles that are adopted in due course as treaties.

The topics certainly speak to governments, but they speak to private practitioners as well. In 1978, the Draft Articles on Most-Favoured-Nation Clauses had a reasonable influence on the fields that practitioners dwell in. We returned to that project in 2015 with a study group report on the MFN clause. So, I do think that these projects have had relevance across the board for governments, practitioners, and scholars.

Maybe the biggest difference between the IBA and the ILC is that the ILC is very much in a symbiotic relationship with governments. The ILC is a creature of governments and international organizations, and it reports regularly to the Sixth (Legal) Committee of the General Assembly. Governments debate the ILC’s reports and react to them. The ILC adjusts its work based on what governments are saying, so that at the end of the day, the completed project is one that has some amount of governmental input.

Once completed, governments may welcome the project and may even launch a treaty negotiation based on the project. I do think that gives the output of the ILC a certain amount of weight. But it is interesting that maybe the IBA has a similar symbiotic relationship with the world of practitioners, such that at the end of the day, when IBA rules emerge, their strength is derived from the IBA’s integration in the realm of private practitioners. And so in that sense, the two bodies have a certain similarity.

Remarks by Joan Donoghue

Thanks, Amir. Thanks to all of you for being here. Thanks for including me. I am happy to see old friends, but especially happy to see the younger faces and students in the room.

Sean mentioned the period just after World War II. I will go back even further because it seems to me that when I study procedures in international adjudication and in arbitration, the mothership is The Hague, and in particular, the Hague Peace Conferences in 1899 and 1907. The imprint of those discussions among men—and they were all men—is visible today in all the nuts and bolts of what takes place in adjudication and arbitration.

When we come back to the present and look at the ICJ, we can ask ourselves where we would find rules. And I use that term loosely, lowercase “rules.” We start with the Statute. However much practitioners and judges might wish to change it, they cannot amend it. Moving forward in terms of specificity, the Court’s own capital R “Rules” would be the next instrument, followed by practice directions that the Court issues to the practitioners who appear before the Court. Then we have the Court’s resolutions on its own internal working methods.

Then I would add two more rule-like elements. One is the developing jurisprudence of the Court on questions of evidence. If you want to understand what the ICJ does with respect to standard of proof, burden of proof, and methods of proof, you have to look at cases, because you will not find this in a written rule. Lastly, a very soft idea of a rule—debatable whether it should be called a rule—would be the expectations that are created among judges and among those who appear before the Court about established practices, i.e., what is generally expected, what is typical.

If we look at all of these in the aggregate, we can ask: what changes have there been in ICJ rules over time? The answer would be that the ICJ changes its rules infrequently. And in general, when there are changes, or even discussions about possible changes, the impetus tends to come from within the Court, not from outside, and not from practitioners.

There is an interesting example from 2016. This was a period shortly after James Crawford joined the court. James came to the court with an extensive background in international law, especially as counsel, and was recused from a number of cases. So he and his then-law clerk, Amelia Keene, organized a review of the Court’s practices. It was very deliberate and well organized.

It started with a survey that was sent to counsel who had appeared before the Court over the ten previous years, and the response level was high. On the basis of that, four high-quality papers were commissioned. Of particular relevance here, one paper was on working methods of the Court, and one paper was on questions of evidence and proof, including experts. A seminar was held with participants from various backgrounds, including counsel, judges, academics, etc. The papers and seminar discussions were presented in an issue of the Journal of International Dispute Settlement, which included a short paper by James Crawford and Amelia Keene that summarized the leading recommendations.Footnote ²

A couple observations about this exercise. First, very few of the recommendations were ever adopted. Secondly, many of the ideas that surfaced in the discussions were ideas that seemed to have been borrowed from arbitral practice, issues that were also swirling around in the arbitration community at the time and that have continued to attract attention today.

For example, there was interest in a case in which the ICJ had propounded extensive questions to the parties, the Ecuador v. Colombia case. These were very technical, scientific questions of the sort that counsel sometimes welcome in arbitration, permitting them to focus on issues of particular importance to the adjudicators. That case actually settled shortly after the questions were propounded.

A related proposal, which will resonate with arbitral practitioners, was a plea for more robust procedural engagement with counsel, including more robust pre-hearing conferences than the procedures that we typically find in the ICJ.

We might ask why more was not done as a result of this seminar. And by the way, there were earlier seminars similar to the one that I have described. There was an event about ten years before this. And the British Institute of International and Comparative Law had organized a study, I think as far back as 1996, that also was looking at ICJ working methods.

We have to say that the ICJ has been conservative in its attitude toward making changes in its procedures. James Crawford told me, after he had been on the Court for a year, that when he joined the Court he had had a variety of ideas of things he wanted to change, and after being on the Court for a while, he had doubts about whether some of those ideas made sense.

This is not to say that, as a former judge, I believe that the ICJ should not change anything. But I think one gains insights from inside an institution that are not visible from the outside. Certainly, I can say there are procedures that would benefit from change. One development that was encouraged in 2016 and that has come about over time, was a plea for shorter hearings. It is notable that this request, coming from counsel, aligned with what the judges also wished to see, not only because they thought it was a valuable in substance to shorten those hearings, but also because of resource constraints on the part of a Court that is much, much busier now than it had been in prior decades.

The other thing to think about, when you think about ICJ judges, is where do they come from? What are their backgrounds in adjudication? Pretty much any arbitrator will have had experience serving as counsel. So their instinct is to think about what a procedure would be like for the counsel. Fewer ICJ judges have experience before the Court, either as an agent or as a counsel.

The other point I wanted to mention is AI. I am glad to hear that the IBA is working on it. The ICJ is not the kind of organization that is going to be first out of the box with AI guidelines, but it will confront the issue, which is everywhere for all of us. AI is a good example of a subject on which ICJ “rules” will likely be developed drawing on work being done elsewhere.

Remarks by Luciana Ricart

Thank you very much Amir. Thanks again for having me on this panel. It is an absolute pleasure. We heard a lot about this topic yesterday for those of you who were at the ITA-ASIL conference. One specific aspect of normative spillover that I would like to draw attention to is the application of the rules of state responsibility on attribution, which are relied upon in investor state arbitration. In my experience, parties’ submissions do not always address these correctly and some arbitral tribunals also misapply these principles. For example, in parties’ pleadings, and sometimes in some arbitral awards, the state responsibility rules on attribution are incorrectly used, treating them as if they were similar to rules of agency or mechanisms for piercing the corporate veil, with the effect of holding the state liable for commercial obligations entered into by separate state entities. While in the context of attribution under state responsibility that is right, I have seen certain awards which fail to draw this distinction. While I do not propose to identify specific awards, it should be noted that some tribunals have acknowledged this distinction and have applied the relevant rules appropriately.

In terms of other possible convergences and divergences, I would highlight the challenge standards applied in commercial and investor-state arbitration and in the interstate context. I want to focus on two decisions on challenges to arbitrators in the context of interstate arbitrations. As we will see, the first one illustrates divergence with the standards applied to arbitrators in the commercial/investor-state context but then in the second one there is a move toward a convergence with those standards.

The first is the November 2011 decision in the context of the challenge to Judge Greenwood in an Annex VII tribunal in the Chagos arbitration between Mauritius and the UK, in which the challenge was rejected. The co-arbitrators noted that the interstate nature of the proceeding was predominant, and that even though Mauritius had referred to the IBA Guidelines on Conflicts of Interest, the co-arbitrators specifically stated that they could not import these rules from private bodies such as the IBA, which had not been expressly adopted by states and did not form part “of a general practice accepted as law, nor [did they] fall within any of the other sources of international law enumerated in Article 38(1) of the Statute of the ICJ.”Footnote ³

In contrast, thirteen years later, a decision in March 2024 in another Annex VII arbitration between Ukraine and Russia, upheld a challenge to Professor McRae and Rüdiger Wolfrum, stemming from their participation in an Institut de Droit International declaration criticizing Russia’s actions. While the decision acknowledged that the relevant standard was the interstate standard of challenges, it specifically noted that developments in other fields like ISDS decisions and the IBA Guidelines were also relevant and should be taken into account.Footnote ⁴

Another divergence would be the contrast in the transparency of the ICJ proceedings, which are public, and the traditionally confidential nature of most arbitrations. However, we are seeing greater transparency in investor-state arbitrations, evidenced by the publication of awards, and also chapters of new free trade agreements and bilateral investment treaties emphasizing transparency, as well as the Mauritius Convention. This move toward transparency in investor-state arbitration is also influencing practices in commercial arbitration.

As to your last question on how my state clients perceive practitioner-led rulemaking efforts, I would say they perceive them with caution, yet simultaneously work closely and in cooperation with practitioners and academics. Based on my observations of the debates and adoption of the Code of Conduct in UNCITRAL Working Group III, and informed by conversations with colleagues who were involved in the debates, it appears that States preferred the discussion to be government-led rather than practitioner-led, though they did draw extensively from practitioners and cooperated with them. Their aim was to adopt specific rules distinct from the IBA guidelines, which were mentioned in the initial reports, but were notably absent from the commentary accompanying the Code.

Samaa Haridi

The Prague rules came out in 2018, and when they came out—largely drafted and proposed by a group of civil law practitioners—the idea behind them was something that reflects civil law traditions more than common law. They characterize the IBA Rules on the Taking of Evidence as essentially a product of common law. But in fact the IBA Rules reflect both legal traditions. But I think the motivation for the Prague Rules was again, to reflect civil law tradition more, and as a result of that, to give the arbitrator more of an inquisitorial role in connection with how to conduct the procedure.

So, the arbitrator under the Prague Rules would have, for instance, the ability to encourage the parties to settle and even possibly act as a mediator. But the arbitrator would also have the last word on whether or not a witness can testify, whether the hearing should in fact occur, or whether the case should be decided on the papers. Another one actually that I think is quite interesting is that the Prague Rules give the tribunal the possibility of applying iura novit curia with the consultation of the parties, which is not something that is addressed in the IBA Rules on the Taking of Evidence.

I think that it would be a simplification to say that one is a common law product and the other one is a civil law product. I do not think that is accurate. If you look, in fact, at the latest iteration of the IBA Evidence rules, you will find that arbitrators are given very significant powers, including in the last amendment, the ability to exclude evidence obtained illegally, for example. That is the reason I say they both provide for different ways in which parties can look at matters of evidence. I think they are both helpful tools, whether codification is a good thing or a bad thing, I hope we have a chance to comment on that later. Thank you.

Joan Donoghue

First of all, I do not think of the IBA rules as common law rules, in the way that they are sometimes depicted. Instead, if you go through them rule after rule, what you see frequently is that the solution for addressing differing perspectives is to leave scope for a range of outcomes in a particular case.

One important variation is the way that the IBA Rules deal with document production. In Rules 3 and 9, you see a lot of detail, but there you have a deliberate decision to come up with something that is not common law or is not civil law, but is also pretty prescriptive. More generally, however, if you look at the IBA Rules and you line them up with the arbitration rules that are governing, or if you look at very similar rules that would govern in the ICJ, the watch word is flexibility.

This flexibility in rules drives the conversations where the participants might have civil law or common law leanings into the individual cases. The participants, whether counsel, agents, judges or arbitrators, may be influenced by the legal traditions in which they were trained. You can see this, for example, when there are questions about experts—whether they should be tribunal-appointed or party-appointed—and especially in decisions about how to approach the cross-examination of witnesses. A U.S.-style, very intense, very pressured cross-examination may look great in an advocacy course in the United States, or before a U.S. court, but does not necessarily lead to the same enthusiastic reaction when speaking to a group of civil law trained judges who may actually find it a bit alienating, causing their sympathies to go toward the witness.

Sean Murphy

I think pretty much all or virtually all international judges or arbitrators would say that their role is not to make the law, but that their job is to interpret the treaty using certain tools, to identify the rule of customary international law, or maybe identify a general principle of law, and then to apply the rule or principle to the facts. And probably that is the case because international courts and tribunals are, arguably, inherently weak institutions, and their strength is derived in a very large measure from the credibility of their decisions. If international judges and arbitrators are perceived as just making up the law, then it is less likely that their decisions be given the weight that they aspire to.

Having said that, I will briefly recall the statement by James Brierly, when speaking about the International Court of Justice, that the act of the Court is a creative act, in spite of our conspiracy to represent it as something else. I think what Brierly meant is it is pretty much inevitable that—when an international court or tribunal interprets a treaty that has a vague or ambiguous term, and then come to some sort of conclusion when applying that conclusion to a particular factual scenario—there is some kind of juris-generative lawmaking quality to it that is just inescapable.

For example, when an international court or tribunal is interpreting a treaty, if it applies a particular maxim or a canon, it is making a choice that advances the understanding of the law. If the international court or tribunal looks back at prior case law that is analogous, but not quite on point, and now applies it to a new setting, there is something juris-generative about that. So, I think we just need to bear in mind that there are inevitable discretionary elements that imbue the art of judging. But this should be done only in a space that is broadly acceptable, because otherwise there would be a question about the credibility, integrity, and legitimacy of the adjudicator.

Joan Donoghue

I will add one point from the perspective of a former foreign ministry lawyer—and many of you have been there. It is five in the morning, it is the eighth day of the negotiation, and there is one bracketed text left. There is a huge impasse, and you come up with an incredibly vague formulation that everyone agrees on, and you are happy that you can go to sleep. Sounds great! Not so great when you are a judge, and that ambiguous term leads exactly where Sean said it would lead.

Luciana Ricart

I would begin by highlighting that some of the most helpful topics from the International Law Commission recently have been the guidelines on the identification of customary international law and its recent work on subsidiary means for the determination of rules of law under Article 38(1)(d). Taking a step back, what do we mean when we are talking about Article 38(1)(d) and the teachings of the most highly qualified publicists? Subsidiary means are important for identifying the rules of international law, that is, customary international law, general principles of law, and treaties. But their role is not to make up the rules or prescribe what the rules ought to be.

However, it is not always self-evident what the rules are. Whether in identifying customary international law and general principles of law, or clarifying the scope of ambiguous terms in treaties, the teachings of publicists serve a subsidiary and auxiliary function in identifying those rules. The International Law Commission—in the commentaries to the subsidiary means and also in the identification of customary international law—has called for caution when considering such writings under Article 38(1)(d), as they may not merely state what the law is, but sometimes advocate for the development of the law. Additionally, the authoritativeness and quality of these sources can vary significantly.

All of this is to say, not every writing should be regarded under Article 38(1)(d), but these writings can serve broader purposes as well. In this sense, numerous works that may not fit under Article 38(1)(d) are still very useful and persuasive in practice. There is, however, another category of works. These are works that are more like advocacy pieces, and I include here works by firms or even NGOs, or academics and practitioners trying to argue what the law should be.

Finally, in terms of how I see the role of these academic pursuits, I do think they are extremely helpful in bridging the gap between theory and practice, and that they play a broader role as we have seen in the development of international law.