Drawing on three theoretical perspectives—“protest-democracy,” “authoritarian/patronal regime dynamics,” and “contentious politics”—developed in the study of popular protests in post-Soviet electoral autocracies, this article argues, first, that the 2020 postelection mobilization in Belarus was not to be expected for both structural and agency-related reasons. Second, by the summer of 2020, the political opportunity structure had opened up because of contingent choices by individual actors, with Alyaksandr Lukashenka committing several major mistakes, particularly on pandemic (non)control and the administration of the upcoming presidential election, and political newcomers taking on the role of challenging him. After the election, mass mobilization unfolded in two waves triggered by two additional regime mistakes: blatant electoral fraud and excessive repression. These mistakes served as focal points for spontaneous coordination, substituting for the deliberate “engineering” of protest by an organized opposition typical of the post-Soviet color revolutions. Third, Lukashenka survived in office because popular protests did not lead to elite defection. Instead, he was able to secure the loyalty of elites because he avoided gross blunders against both regime insiders and Russia. The case of Belarus indicates that hegemonic-authoritarian regimes are more vulnerable to mistakes by incumbents than to challenges from below and outside the regime.