Keywords: Processes of Radicalization, Political Violence, Historical Comparative Method, Relational Factors
In this article, through comparative historical research, the authors seek to account for the "how" and "when" of the shift to political violence of the Weather Underground and of the Provisional Irish Republican Army. The focus is not on deep-rooted "causes", but on analyzing the dynamic processes of radicalization in the two historical contexts separately according to relational factors (competition for power, opportunity/threat spirals and outbidding). At the end of the article the authors focus on the dissimilarities found between the two processes and accordingly embed their explanation within the more general historical debates on the subject. In the conclusion, the article briefly points out the promise the authors find in their approach as a possible comparative framework for the analysis of radicalization.