Under what kinds of circumstances do vigilante activities emerge, flourish or fail? What are the facilitating and impeding conditions? These issues are examined in an international comparative study with case studies of vigilante groups in 17 countries. Several conditions – especially when they appear in combination – create opportunities for vigilantism in general, and directed against migrant and minorities in particular. The presence and/or absence of some of the factors are more likely to produce certain types of vigilantism and not others. For example, countries with permissive gun laws and historical traditions of militias are likely to foster armed militia vigilantism. Where these conditions are absent and there is very limited or no acceptance for paramilitarism and vigilantism, non-violent street patrols are more likely to be the main form of vigilantism to appear. Vigilante groups and activities tend to emerge and flourish in settings when there is a convergence of several facilitating conditions and an absence of impeding or repressive factors. They fail and decline when the facilitating conditions are reduced and repressive measured are implemented against them.
