Abstract Under what conditions has corporatist policymaking become institutionalized in newly transitioned democracies? I argue that transitions have provided temporary opportunities for unions to push for laws they can later use to protect their place in economic councils. The relevant sets of legal rules, which I call compulsory deliberation, enable non-‘State official’ members to resist governmental disruption of such councils despite them composing the Executive’s structure. I compare South Africa and Brazil, two ‘most similar’ cases that featured sequences of chronically unstable labor-excluding councils under authoritarian regimes. I argue that the former broke out of this trajectory while the latter did not because South African unions developed aspirations for durable policy influence before the transition, whereas Brazilian ones only did so afterward and thus mobilized too late. Although Brazilian governments have enacted dozens of regulations covering as many councils, these have only served as short-term instruments for marketing policies.