- American Society of International Law
President 2000 - 2002; Executive Council 1997-present;
Board of Editors American Journal of International Law 1977-1987.
- American Bar Association
Chairman International Law Section 1985-1986;
Section's Delegate to the ABA House of Delegates 1986-1987.
- Council on Foreign Relations
- Association of the Bar of the City of New York (Arbitration Committee)
- Center for Public Resources (Panel on the Settlement of Transnational Business Disputes)
- U.S. Council for International Business (Arbitration Committee).
- LCIA member
- ICC list of arbitrators
- American Arbitration Association/ICDR list of arbitrators
- ICSID arbitrator
- NAFTA arbitrator
