Dissident movements are the mobilizations of the resources of aggrieved citizens against elites. Citizens use their resources in unconventional political ways to redress their grievances by pressuring regimes to grant them concessions. When elites are unable to cope with movements, they themselves accumulate grievances against dissidents and mobilize their resources, including supportive citizens or vigilantes, to quash dissents. Vigilantism should not be viewed as an isolated, random, static phenomenon, but as a systematic part of a broader countermovement dynamic. Elites themselves use unconventional political means, such as vigilante groups, against unconventional dissidents. As such, vigilante groups are a political mirror- image of dissident groups. The propositions central to this theory fall under three rubrics: origins, behaviors, and consequences. This article presents 16 propositions that address the concepts under these three rubrics. Strategic implications of this theory for human rights groups are grouped under three rubrics as well: prevention, formation of disbandment coalitions, and protection of actual and potential victims. 102 notes