Focuses on how and why parliamentary systems of governance have accommodated constitutional review. The American and European models of constitutional review are contrasted, and the history, structure, and function of European constitutional courts are surveyed. The necessity of review in defending human rights and its conceptualization as a means of completing the constitution over time are found to be particularly important across these cases, but factors explaining the variance in the judicialization of European law‐making are also identified. The chapter ends with a discussion of the main determinants of European constitutional politics.