Analyses often interpret ‘terrorism’, as we have mentioned, to be degeneration facilitated by repression, the progressive closure of the political system, and social isolation. This is the case, for example, for Wieviorka's (1988) anti-social movement paradigm or for Tarrow's (1995) idea that radical groups generally appear in the demobilization phase of a protest cycle. We can make the assumption that radicalization is more likely to occur among those who did not experience the initial phase and joined the movement later, which seems to be corroborated by greater levels of violence among second- and third-generation militants.

Four variables will be considered here: the degree of repression; the group's relations with the benchmark revolutionary subject; social movement organizations and their relations; and the micro-sociological level, limited here to reflection on the cognitive and emotional effects of functioning in small groups insofar as our knowledge of the individual determinants of radicalization are very fragmentary outside of the Italian and, to a lesser degree, German cases.

Two precautions should be taken. On the one hand, it should be remembered that none of these dimensions has a mechanical and linear effect because depending on the temporality of the movement, they each have distinct effects, i.e. in the initial phase when inclinations are formed, in the armed struggle phase when levels of violence rise, and finally, in the disengagement phase. They will also partly resurface to explain the processes of exiting the crisis. On the other hand, these dimensions are interconnected, and combine with one another; it is therefore only for illustrative purposes, and in order to identify general tendencies, that we can consider that any one of these dimensions might explain a given case.

Repression and Counter movements

If we follow Tilly's reasoning, repression has a curvilinear impact on mobilization, and thus a major radicalization effect when it is at its mid-point. Repression, whether continuous or suddenly accelerated, was a decisive factor in several of the countries studied here.

Germany

For all the groups studied here, it was indeed often a repressive event that triggered the radicalization process, placing them in a cycle of provocation repression- violence.