Scholars have shown that nonviolent movements tend to be more successful than violent movements. A key explanation is that nonviolent movements have a mobilization advantage over violent campaigns. As nonviolent movements have lower barriers to active participation, they can expand quickly by mobilizing much larger numbers than violent movements. We argue that such a mobilization advantage is not universal, and that different movements are likely to have a comparative advantage in one tactic over another. We develop a simple model emphasizing how the ex ante potential for mobilization and prospects for success steer the choice of dissident tactics. Nonviolent tactics can be relatively more effective when a movement can mobilize more active participants than with violence, but movements with limited mobilization potential can have feasible prospects for violent dissent and a nonviolent mobilization disadvantage. We examine the implications of the model against empirical data for different types of dissident tactics and on resort to nonviolent and nonviolent dissent. We demonstrate very different actor profiles in nonviolent dissent and violent conflict, and show how each of the two types of dissent are more likely under very different settings. To compare success by types of dissent we must account for how differences in potential numbers or mobilization shape tactical choices.