Legacy unions—formerly state-backed unions that survived democratic transitions—are one of the most persistent legacies of authoritarian rule. While usually successful in maintaining their preeminent position, legacy unions have in some cases been overtaken by competing unions. Deploying a set of paired comparisons of legacy unions that entered the transition with similar legacies but experienced different fates—Indonesia with South Korea and Poland with Russia—this article examines why some legacy unions continued to dominate (Indonesia and Russia) and others did not (South Korea and Poland). The author identifies four pathways of change: endurance (Indonesia), attrition (South Korea), hegemony (Russia), and rupture (Poland). Several features of the transition context propelled legacy unions down distinct pathways of change—the widespread mobilization of workers outside of state-sponsored unions early in the transition, partisan links, and the structure of union competition.