Which thinker merged Aristotelian ideas with Christian philosophy, influencing modern constitutionalism?

St. Thomas Aquinas is recognized for merging Aristotelian ideas with Christian philosophy, which played a significant role in shaping modern thought, particularly in the context of constitutionalism. Aquinas integrated Aristotle’s philosophy, especially his ideas about natural law and ethics, with Christian theology, creating a framework that justified governance based on moral principles derived from both faith and reason. This synthesis influenced the development of political theories that emphasize the importance of law, justice, and the common good, which are foundational to modern constitutionalism.

Through his works, especially the "Summa Theologica," Aquinas articulated the idea that human laws should reflect eternal laws and natural rights, establishing a moral basis for civil authority and governance that resonates in contemporary constitutional frameworks. His contributions set the stage for later thinkers who expanded upon these principles, emphasizing the role of individual rights and the need for governance to align with ethical norms. Thus, Aquinas’s work is central to understanding the intersection of philosophy, theology, and the evolution of political structures in the context of constitutional development.