Ireland and the United States: Two Tales of Natural-Law Constitutionalism

To what extent is natural-law theory relevant to modern constitutional jurisprudence? This paper seeks to answer that question by comparing how courts in Ireland and the United States have used, and continue to use, natural-law reasoning in interpreting their constitutions’ fundamental-rights provisions. Natural law is relevant despite decisions that disclaim reliance upon it. Whether implicitly or explicitly, natural law seems to undergird certain provisions of both nations’ constitutions, and therefore natural-law reasoning seems to be inescapable. By a comparison of these constitutional provisions and the jurisprudence surrounding them, this paper will demonstrate that natural-law reasoning is inherent in constitutionalism, particularly as it pertains to fundamental rights. Even so, various mechanisms of addressing the natural-law basis for fundamental rights have proven more or less enduring and successful, providing insights for natural-law constitutionalism in other countries.