YouTube-based discussions are a growing area of academic attention. However, we still lack knowledge on whether YouTube provides for forming critical publics in countries with no established democratic tradition. To address this question, we study commenting to Belarusian oppositional YouTube blogs in advance of the major wave of Belarusian post-election protests of 2020. Based on the crawled data of the whole year of 2018 for six Belarusian political videoblogs, we define the structure of the commenters’ community, detect the core commenters, and assess their discourse for aggression, orientation of dialogue, direction of criticism, and antagonism/agonism. We show that, on Belarusian YouTube, the commenters represented a genuine adversarial self-critical public with cumulative patterns of solidarity formation and find markers of readiness for the protest spillover.