Legality and Reciprocity: A Discussion of Lon Fuller's The Morality of Law

Lon Fuller’s book The Morality of Law is one of the richest books of legal philosophy of the twentieth century.1 I do not think it has attracted the attention it deserves and I welcome the opportunity to renew interest in it through the pages of this Review.2 My topic will be the contribution that the Morality of Law makes to our understanding of constitutional law. In my view, Fuller’s moral conception of legality provides an answer to one of the deepest questions of constitutional law, namely the question of the requirements, if any, for the existence of a legal system. Most legal positivists locate the creation of legal systems and constitutions in some empirical event. Fuller disagrees. Fuller’s view of law identifies it with a moral ideal of the rule of law, not just the rule by law. In the view that I will defend, Fuller’s book introduces...