Studies of protest have argued that repression “backfires”—it activates indignation and galvanizes resistance. However, most activists know that this is not always the case. When does repression actually expand the ranks of social movements, granting them the “critical mass” needed to pressure authorities and win concessions, and when does it not? This paper distinguishes between private and public forms of repression and argues that behind-the-scenes, targeted repression by private actors is much less likely to backfire. Ethnographic and comparative research of mining conflicts in Peru uncovers how mining corporations marshal the state’s coercive apparatus as well as private intelligence, security, and media into a type of corporate counterinsurgency operations. Overtly and covertly, these work to delegitimize, intimidate, and demobilize opponents, with direct effects on the capacities and strategies of resistance.