The defeat of terrorist groups in the 1980s and 1990s should be the starting point for any discussion of potential domestic terrorism. That era tells us what works and what doesn’t. Heavy-handed military style approaches, employed initially by the British in Northern Ireland, do not succeed. Relying on the existing courts and law enforcement does work because the justice system has an inherent legitimacy. Identifying terrorists as criminals and dealing with them as such openly and transparently through the criminal justice system provides a guarantee of at least a modicum of due process, particularly when honest efforts are also made to obtain the support and cooperation of the moderates in the local community. That is how the Red Brigades, Baader-Meinhof, ETA, and the IRA were eventually brought to heel.