There is perhaps no more important access point into the key issues of modern political and legal theory than the questions raised by the interaction of law and religion in contemporary constitutional democracies. Of course, much classical political and moral theory was forged on the issue of the relationship between religious difference and state authority. John Locke’s work was directly influenced by this issue, writing as he did about the just configuration of state authority and moral difference in the wake of the Thirty Years’ War. Yet debates about the appropriate role of religion in public life and the challenges posed by religious difference also cut an important figure, in a variety of ways, in the writings of Hobbes, Rousseau, Spinoza, Hegel, and much of the work that we now view as being at the centre of the development of modern political philosophy.