He is a member of law firm Caplin & Drysdale, Chartered, and is the James S Eustice Visiting Professor of Taxation and Director of the International Tax Program at New York University School of Law. A frequent speaker and author on tax, he has taught international taxation at Stanford, Columbia, Harvard, Pennsylvania and New York universities, and at educational institutions around the world including Melbourne Law School. He has also served as a Tax Policy Adviser for the United States Treasury, the Organisation for Economic Cooperation and Development (OECD), AID, and the World Bank in Eastern Europe, the former Soviet Union, Senegal, Malawi and South Africa.