To grasp accurately what has been involved in the invention of the modern constitutional republic it is necessary to select a relatively ample framework, both of chronology and of geography. The key practical episodes in this passage of invention may have taken place (as is conventionally agreed) in eighteenth-century north America and France. But it has required most of the twentieth century to clarify even their most essential implications; and it is a trifle sanguine to assume that all of their major implications are yet apparent even today.

At present the modern constitutional republic stands virtually unchallenged as the sole surviving candidate for a model of legitimate political authority in the modern world. It does so, to be sure, in a fairly distinct form – and in a form the merits of which were far from uncontroversial in the north America of the 1780s or the France of the early 1790s. All modern constitutional republics of any longevity now profess to be democracies (as do many regimes which are far from constitutional in the sense in question). Their overt claim to legitimacy is now a direct function of their claim to be democracies. But this last pretension must be understood not as the intrinsically heady classical claim to realise ancient liberty – the claim that the sovereign political community is simply identical with the free public acts of its free citizens – but rather as an instrumental precondition for enjoying (and an assertion of the popular entitlement to enjoy) the more tepid, if more dependable, charms of modern liberty.