Taking its cue from Benjamin Constant’s famous comparison of the liberty of the ancients with that of the moderns, this article examines the compatibility of democracy with free markets within the EU. Constant argued that commerce had replaced the political liberty of the ancients with the civil liberties of the moderns. Nevertheless, he contended a degree of political liberty remained necessary to guarantee these civil liberties. The difficulty was whether the political system could operate in the interest of all if modern citizens had ceased to identify with the public interest in the manner of the ancients and preferred to pursue their private interests. Constant believed representative democracy offered a form of political liberty that was compatible with modern liberty. It involved a less demanding view of civic virtue to ancient liberty and a different conception of the public interest as promoting rather than in conflict with private interests. However, for it to operate as Constant expected required certain social and cultural conditions that emerged in European nation states but are not themselves the products of commerce and may even be undermined by it: namely, a national identity; a social contract; and political parties. The EU involves a further deepening of modern commercial liberty beyond the nation state. This article explores three main issues raised by this development. First, have any of the three elements that facilitated the operation of representative democracy within the member states evolved at the EU level? Second, if not, is it possible to create an effective form of representative democracy on a post-national basis as the logical entailment of the liberties of the moderns? Third, if neither of these is possible, can we simply detach modern liberty from political liberty and see social rights as attributes of free movement, and efficient and equitable economic regulations as the products of technocratic governance? All three questions are answered in the negative.