Is state repression effective in demobilizing dissidents? While some studies find that repression can be effective, at least in the short term, a strand of this literature doubts its effectiveness due to backlash mobilization. However, despite widespread discussions, studying the underlying mechanisms through which the backlash mechanism influences dissidents and their mobilization has received limited attention. This study argues that the rise of social media platforms for keeping and sharing personal diaries, especially among the younger generation, increases the likelihood of backlash mobilization in response to the state’s violent response to protests. Building on scholarship from psychology and communication science, I develop a theoretical framework to explain how the digital diaries of the victims of state repression brace protestors and increase social cohesion among dissidents. The study examines the proposed theoretical arguments by analyzing the nexus of repression-protest during the “Woman, Life, Freedom” revolutionary uprising in Iran. I use machine learning to analyze an originally collected dataset on the digital presence (image, video, and text) of citizens killed by the state and data on street protests and online campaigns to show that digital diaries have created online and offline backlash effects.