How can autocrats be restrained from rigging elections when they hold a huge military advantage over their opponents? This article suggests that even when opposition parties have no military capacity to win a revolt, opposition unity and a consequent threat of massive civil disobedience can compel autocrats to hold clean elections and leave office by triggering splits within the state apparatus and the defection of the armed forces. Opposition unity can be elite-driven, when parties unite prior to elections to endorse a common presidential candidate, or voter-driven, when elites stand divided at the polls and voters spontaneously rebel against fraud. Moreover, the article identifies some conditions under which autocrats will tie their hands willingly not to commit fraud by delegating power to an independent electoral commission. The article develops these ideas through a formal game and the discussion of various case studies.