Should constitutional jurisprudence employ the vocabulary and methodologies of moral philosophy? This question is central to an important and recently revived debate within legal theory. As legal theory has increasingly turned to the theories and methods of other disciplines, a number of important theorists have explored the role of moral philosophy in legal reasoning. Although law and morality have long been viewed as intertwined in some manner (at least by some theorists), the recent debate presents a more nuanced view of that relationship. On one side, proponents assert that the apparatus of moral philosophy is inseparable from sound constitutional law. On the other, opponents claim that moral phi-losophy is both indeterminate as to results and illegitimate as a means to derive constitutional doctrine. These debates often go to the heart of the proper definition of “law” and the appropriate mode of interpreting our Constitution.