Louis Kriesberg (2007) writes about what we might call the bell curve of conflict, the increasing success of bold and confrontive challenges and the decreasing success once the line of violence is crossed. "Strikes involving violence are more likely to fail than are work stoppages without violence." However, "Challengers who act disruptively to gain attention and to exercise pressure against their opponents tend to be more successful than are challengers who are not unruly." (p. 302)
Of course, every situation is different. We have seen what a major effect the external actors play, from Egypt to Bahrain, from Tunisia to Syria, and how that also moves and heightens or flattens that bell curve. No single factor is dispositive. Only tendencies are noteworthy and can be claimed.
But the tendencies should inform strategic planners and help them design plans, campaigns, and the trainings to support the mass actions needed to enable a civil society victory. Educating and training masses of people to learn how to be engaging and interesting even as they are being a direct and powerful challenge is the way to both protect the people and help them gain the most. Anything else is either shirking from the structural violence of injustice in a passive hanging-back defeatism or an aggressive and unnecessarily sacrificial suicide action. Effective mass action is the sweet spot of Tahrir Square. The other end is the quietude of a beaten down populace in Gambia on the one hand or a needless bloodbath like Libya on the other.
The lines are thin but bright and the risks and rewards are large. Playing it right takes keen and sensitive antenna and profound preparation.
Kriesberg, L. (2007). Constructive conflicts: From escalation to resolution (3rd ed.). Lanham MD: Rowman & Littlefield.