This thesis investigates judicial preview from a comparative law perspective by analyzing the Swedish Lagrådet (Council on legislation) and the French Conseil constitutionnel (The constitutional council). The study examines how rules on member appointment, composition, and competence might have an impact on the legitimacy of these institutions, where legitimacy is understood as public trust in the legal order. The discussion is framed in relation to the constitutional balance between enhancing rule-of-law legitimacy through legal expertise, and safeguarding popular sovereignty in a representative democracy. The findings show that Lagrådet enjoys strong rule-of-law legitimacy due to statutory requirements of judicial expertise and independence. Furthermore, Lagrådets democratic legitimacy is strengthened through its non-binding opinions, however, to some extent, at the expense of its institutional authority. Conversely, the Conseil constitutionnel wields binding powers to invalidate legislation, despite political appointments of members, and absence of formal competence requirements, thereby weakening both democratic- and rule-of-law legitimacy. This is where the imbalance between competence and authority reveals itself. However, the thesis concludes that these contrasting institutional models stem from different constitutional contexts and institutional purposes, which are factors that, within the framework of the legal order to which they belong, explain the legitimacy of both councils.