ABSTRACT Terrorism systematically violates human rights and disrupts basic political processes common to liberal democracies. Combating terrorism is thus necessary in order to protect these fundamental rights and maintain the well functioning of tolerant polities. However, state initiatives put in place to cope with terrorism may also damage human rights, even when these measures are formulated by elected accountable authorities and implemented in the context of open societies. Spain has precisely been among those European countries most affected by the wave of terrorism initiated more than three decades ago across western industrial societies, and thus where violations of fundamental rights as well as obstacles to the exercise of civil liberties as a consequence of such violence became particularly severe. Also, a case where effective rule of law was temporarily damaged in the fight against the ethnonationalist terrorism perpetrated by ETA (an acronym for Euskadi ta Askatasuna, meaning Basque Homeland an...