What is domestic terrorism, and why is it so difficult to combat? Here, Simon Cleveland, Ph.D., faculty director of Georgetown University’s Bachelor of Arts in Liberal Studies program, puts those questions to two faculty members: Paul Lewis, a former national security advisor to President Obama; and Bill Buckley, Ph.D., author of numerous publications on ethics and international affairs. The problem, Lewis said, isn’t our surveillance ability; we have plenty of cameras and listening devices. It’s the sheer immensity of the task— “billions, if not trillions of bits of information” to sort and possibly analyze. Domestic terrorism has been rising for several years, Buckley said. Among the many explanations are a sense of “aggrieved entitlement” among extremist groups, and the mass deinstitutionalization of mental patients that occurred between 1955 and 1995.