A utilitarian argument: laying the foundation for a coherent system of law

Even the most ardent legal positivists agree that as a matter offact there is a connection between law and morality. In most Western legal systems this association is very strong. Underpinning most legal rules is a (real or  purported) moral principle - certainly it is difficult to find examples of laws which are clearly immoral. The foundation upon which a coherent and justifiable legal system must be built is a theory of morality.