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Who's Who Legal
Who's Who Legal
Thought Leaders

Thought Leaders

Thought Leader

WWL Ranking: Thought Leader

Peers and clients say

"He possesses deep knowledge of investment arbitration"
"Bart has an excellent reputation"
"He is strong as counsel"

Questions & Answers

Bart Legum is global co-chair of litigation and dispute resolution for Dentons, the world’s largest legal practice. He has over 30 years’ experience serving as counsel or arbitrator in complex international disputes. He is a member of the board of the Arbitration Institute of the Stockholm Chamber of Commerce and the ICSID Panel of Conciliators (appointed by ICSID) and serves as editor of The Investment Treaty Arbitration Review and International Litigation Strategies and Practice. 

Describe your career to date.  

After studying public international law for a year at the Paris II law faculty, I returned to my native US to clerk for a federal appeals court judge. I then practised at Debevoise & Plimpton in New York for 13 years litigating a wide variety of civil and commercial cases, most containing a cross-border element. My career in arbitration began in earnest at the end of the last century. The US State Department recruited me to lead the US defence of the first arbitrations against it under the NAFTA’s investment chapter. I led the State Department NAFTA team from 2000–2004, winning every case heard during my tenure.

Love led me to move to Paris. I have practised international commercial arbitration and investment treaty arbitration here for the past 17 years. My practice has primarily been as counsel, but I increasingly sit as an arbitrator and as a mediator.

How do you prepare for complex cross-border arbitration proceedings?  

Reading, reading and more reading. My goal is to understand the issues sufficiently before the hearing to identify the key questions I would like answered. Ideally these questions are posed to the parties sufficiently in advance for counsel to take them into account at the hearing. But this is possible only if the other arbitrators can also prepare themselves to this level well before the hearing.

What do you believe are the most important issues for clients when looking to begin an arbitration? 

The key is to understand that there is only one chance to win. The absence of an appeal means that in arbitration there is no second chance. Arbitration requires an intensity of effort and focus in preparing the case that may be different from that in court litigation.  

How has the role of arbitrator changed since you started your career?

The role has not changed as much as the users’ expectations. Users today expect a higher degree of professionalism, technical expertise, devotion and responsiveness.  

What are the challenges of managing an abundance of data and information? How can these challenges be overcome?

My practice has been paperless for about a decade. Taking this step provided me with a significant productivity boost. Being able easily to access any relevant document concerning the case from anywhere at any time makes a huge difference. This makes working remotely or while travelling much more efficient.

What trends do you see currently emerging in international arbitration? 

A significant uptick in arbitration work in all sectors.  

What impact has covid-19 had on investor-state arbitration?

Some additional delay in procedural schedules, but not as much as in other fields. The more important trend is that more meetings and hearings are held online. I expect that this trend will continue going forward, at least for shorter hearings that involve no witness testimony.

Looking back over your career, what is the most interesting arbitration you have been a part of?

I actually find all of my cases to be interesting. It is hard to single out one in particular, but what comes to mind is the Methanex v United States case. It came at a time when there was little jurisprudence to guide the debate, presented a perfect storm of policy issues and the hearing featured a fascinating “play within the play”:  there was an evidentiary hearing on whether certain evidence had been illegally obtained that took place during the merits hearing, with a different cast of characters and a different set of issues to be decided.

Global Leader

Arbitration 2021

Professional Biography

WWL Ranking: Recommended

Peers and clients say

"He possesses deep knowledge of investment arbitration"
"Bart has an excellent reputation"
"He is strong as counsel"


Barton Legum is a partner in Dentons’ Paris office and head of the firm's investment treaty arbitration practice. Bart has over 30 years' experience in litigating complex cases and has argued before numerous international arbitration tribunals, the International Court of Justice and a range of trial and appeals courts in the United States. His practice focuses on international arbitration in general and arbitration under investment treaties in particular.

He is a past chair of the American Bar Association’s section of international law, an international bar organisation with over 24,000 members from over 90 countries around the world. In September 2017, the president of the World Bank appointed Bart to the ICSID roster of conciliators for investment disputes.

Earlier in his career, Bart served as chief of the NAFTA arbitration division in the office of the legal adviser, United States department of state. In that capacity, he acted as lead counsel for the United States government in some of the first arbitrations under the investment chapter of the North American Free Trade Agreement (NAFTA). The United States won every case decided under his tenure.

He is the editor of The Investment Treaty Arbitration Review (5th ed 2020), an annual publication of Law Business Research. He is also a founding editor of International Litigation Strategies and Practice (1st ed 2005; 2nd ed 2014), a book published by the American Bar Association. Bart is often published on international dispute resolution topics and frequently speaks at conferences on international arbitration and litigation.

WWL Ranking: Recommended

National Leader

WWL Ranking: Recommended
WWL Ranking: Recommended
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