It's been a bad few weeks in Sri Lanka, where a major terrorist attack—the largest since 9/11—hit multiple locations targeting Christians on Easter morning. The violence was different from the usual terrorism that rocks Sri Lanka from time to time. Benjamin Wittes sat down with Christine Fair, an expert on South Asian politics and extremist groups, talked through what's going on in the island nation. How does it map onto the history of ethnic tensions between Tamils and Sinhalese? And what does it mean for the future of Muslim extremism in South Asia?