This study examines the theoretical foundations and judicial mechanisms of constitutional review across comparative legal systems, with a specific focus on the Iraqi experience.It explores the relationship between constitutional supremacy,the separation of powers,and judicial independence, as well as the impact of these principles on defining the nature and limits of such review.The study addresses the question of whether the constitutional and legislative frameworks governing review are sufficient to ensure legislative compliance with the constitution,protect rights and freedoms,and maintain stability of legal position,particularly given the variations in competent review bodies,the procedures for initiating review, and the legal effects of the resulting rulings.A descriptive,analytical,and comparative methodology was employed,involving an overview of the judicial and political theories of constitutional review, an analysis of the constitutional and legislative bases for the jurisdiction of Iraq’s Federal Supreme Court, and a comparison of centralized versus decentralized review models,as well as hybrid systems combining*a priori*(pre-enactment) and*a posteriori*(post-enactment) review. The comparative analysis encompassed the US experience alongside aspects of the French, Egyptian, Bahraini, and Turkish systems to highlight differences regarding jurisdictional organization, access to constitutional adjudication, and the binding force and effects of rulings. The study concludes that the effectiveness of constitutional review depends on the independence of the reviewing body, the clarity of its jurisdiction, and the precision of its procedures. Centralized review fosters uniformity in constitutional interpretation and judicial specialization, whereas decentralized review broadens the role of courts in upholding the constitution—albeit necessitating mechanisms to reconcile divergent judicial interpretations. Finally, the study underscores the importance of distinguishing between direct constitutional actions and pleas of unconstitutionality as distinct avenues for initiating review, as well as the significance of how the authority to adjudicate the constitutionality of laws is distributed.Leveraging ex-ante legislative review allows for the mitigation of constitutional flaws,provided that its relationship with*ex-post*judicial review is clearly defined.