Abstract

The hypothesis that terrorism often emerges when mass collective action declines and radicals take up arms to compensate for the weakness of a mass movement has been around for some time; however, it has never been tested systematically. In this article the authors investigate the relationship between terrorist violence and mass protest in the context of the Spanish transition to democracy. This period is known for its pacts and negotiations between political elites, but in fact, it was accompanied by high levels of terrorist violence and popular mobilization. To test the hypothesis, the authors have created two data sets, one on victims of terrorism and another on participation in demonstrations. The data clearly confirm that terrorism erupted in Spain when participation in demonstrations started to decline. This result sheds new light on the nonstructural conditions associated with the onset of terrorist violence.