Oppositions in electoral authoritarian regimes often boycott sham elections. Yet unfair elections can be game-changing. This article shows how the opposition contested the 9 August 2020 presidential election in Belarus to mobilize a large-scale grassroots prodemocracy movement by: 1) presenting a credible alternative to the regime and unifying efforts, 2) drawing on citizen-led initiatives—including an innovative artificial-intelligence parallel vote-tabulation system—to expose the extent of electoral manipulation, build solidarity, and engender belief in the possibility of change, 3) involving citizens at every stage of the electoral process to credibly demonstrate support for the opposition, and 4) wielding the regime's electoral law against it to publicize electoral violations. The election transformed Belarus's once-apathetic populace into active citizens and created conditions for future change, despite mass state-sanctioned violence.