The recent global wave of autocratization is characterized by the incremental subversion of democracy from within by elected governments (democratic erosion). This article explains why democratic erosion is hard to reverse for opposition actors, even though it develops incrementally and often by using formally legal and democratic means. Complex causal mechanisms triggered by what we call regime uncertainty create specific dilemmas dividing opposition actors at elite and mass levels into alarmists, strategic alarmists, and cautioners. The resolution of these dilemmas takes time, learning, and creativity and there is no one-size-fits-all formula: our case studies from Venezuela and Turkey show that opposition actors often experiment and oscillate between normal and extraordinary countering strategies and between preservative and generative political goals. We also offer a preliminary discussion of how opposition actors may manage to address the dilemmas and successfully counter democratic erosion.