He teaches and researches in the fields of imperial and legal history, human rights, and peace/conflict studies. He has taught in universities in Africa, Europe and the United States. He was previously a Human Rights Research Fellow at the Carnegie Council for Ethics and International Affairs, New York and Research Fellow at the Danish Institute for Human Rights, Copenhagen. He has served as a consultant to the Constitutional Rights Project and the Canadian Museum of Human Rights. He is the author of Imperialism and Human Rights (SUNY Press) and Imperial Justice (Oxford University Press).