Navigating Violence between Surface and below: Effect of Protester Reaction to Violent Flanks on Mobilization

Abstract How do nonviolent protesters’ responses to violent flanks shape mobilization in unarmed movements? Existing research rarely centers on these responses, instead estimating a single net effect of violent flanks with mixed results. This article argues that the effects of responses hinge on fragmentation discrepancy, the gap between how unified a movement appears to outsiders and how cohesive it is internally. As responses to violent flanks (endorsement or opposition) operate as outward public signals and internal organizing devices, their effects on mobilization vary with the fragmentation discrepancy’s sign and size. Using NAVCO 2.1, ACLED, and an illustrative case of Hong Kong’s 2019 anti-extradition movement, I show that endorsement increases mobilization when movements look unified but are internally divided, whereas opposition is more effective when movements appear fragmented yet are internally cohesive. These results reconcile mixed findings on violent flanks and re-center protesters’ agency in explaining mobilization.