The Islamic Republic of Iran prides itself on being the only country with an entirely codified Islamic legal system, and on being a pioneer in the Islamization of constitutional law. Part 1 of this chapter provides an overview of the different models of Islamic constitutionalism currently found in the Muslim world. Part 2 reviews Iran’s highly creative and ambitious project of Islamizing an entire civil law system and codifying Islamic law over a forty-year period and draws attention to the high degree of dynamism and reinterpretation of Shiite legal precepts that this project has required. Part 3 focuses on the making and amendment of Iran’s 1906/1907 and 1979 constitutions – which fused foreign, republican, and Islamic elements in unique ways – and on the role of the 1979 constitution in defining and regulating Iran’s distinctive present-day blend of institutional conflict and policy disagreement among religious conservatives, pragmatic reformers, and revolutionary leftists. Over time, a combination of innovative reinterpretation of Shiite legal principles and constitutional and institutional reform have reshaped the complex relationship between left-leaning legislative institutions constrained by Islamic principles and conservative religious scholars who operate outside the political system but are the arbiters of what it means to respect Islamic principles.

Mirjam Künkler & David S. Law, Islamic Constitutionalism: Iran, in Constitutionalism in Context, Cambridge University Press, 449–473 (2022).