This article examines two outcomes of demobilization in post-revolutionary contexts, democratic transition and counter-revolution. Complementing elite-driven approaches, we argue that the way demobilization ends is conditional upon the capacity of challengers to promote enduring alliances. Following a paired controlled comparison, we analyse two cases, Egypt and Tunisia and processes of alliance building and fragmentation preceding the 2013 coup d’Etat in Egypt, and the adoption of a new Constitution in 2014 in Tunisia. Data from semi-structured and in-depth interviews were collected through fieldwork in multiple localities of Egypt and Tunisia between 2011 and 2019. Results show that the fragmentation of the challengers’ coalition in post-revolutionary Egypt contributed to a counter-revolution while, in Tunisia, challengers’ alliances rooted in the pre-revolutionary period lasted throughout the phase of demobilization and supported a democratic transition. We conclude by discussing some alliance-based mechanisms accounting for a democratic transition: intergroup trust-building, brokerage and ideological boundary deactivation.