As a leftist student leader and a member of Janatha Vimukthi Peramuna (JVP) movement in the 70s, he was arrested and imprisoned by the government. After the change of regime he went on do his doctoral research in the University of Hawaii on ‘Nationalism and State Formation in Bangladesh. He remains one of Sri Lanka's most controversial commentators on ethnic conflict and human rights. He was involved with Dr. Neelan Tiruchelvam in drafting the model constitution in 1999.
He is presently Head of the Department of Political Science and Public Policy at the University of Colombo; and Founder-Director of the Centre for Policy Research and Analysis, Colombo. He is former Chairman of the Sri Lanka Foundation, Colombo.
He was the Founder Editor and later co-editor of Pravada, an academic journal in English that focuses on Sri Lanka and South Asia. He continues to write prolifically in Sinhala and English.
He was for two periods in the 1980s a resident of the intellectual neighbourhood of Welikadawatte.