This paper addresses questions of legal and political theory concerning representations of law, sovereign power and justice within Shakespeare’s most famous tragedy. DiMatteo has effectively demonstrated how Hamlet can be seen as a critique of the theory of sovereignty based upon reason of state, a revelation of the consequences of failing to consider the proper constraints that can and should be placed upon sovereign power by common reason. I explore how the play emphasises the significance of the restraints that can be placed upon the sovereign and indeed, Hamlet himself, by natural law and justice. Applying the natural law theories of Shakespeare’s contemporaries and John Finnis’modern theory of natural law, I will argue that Claudius is an illegitimate figurehead of state and law whose exercise of practical reason and prudentia is flawed, and that his actions cause his law to lack the moral content demanded of ‘law’ worthy of that name. Whilst Claudius’ rule is that which the people of Denmark actually experience in Hamlet,until the end of the play, the Danish people face the prospect of Hamlet’s future reign as Claudius’ successor. Thus, in part II of this paper, I will assess Hamlet’s unfulfilled potential as a sovereign lawmaker and consider whether his philosophical, cautious nature would have been apt for this role.