Abstract The EU Treaty contains for the first time a title on democratic principles. These provisions emphasise the importance of national parliaments and the EU parliament for the democratic legitimacy of the EU. The new chapter on democratic principles does not address the central challenge of the EU polity to the traditional understanding of democratic legitimacy, the disjunction of political and economic governance as expressed by the important role of independent institutions like the Commission, the European Central Bank and agencies in EU governance . This is a consequence of the fact that the status of independent regulatory institutions in a democratic polity has not been clarified—neither in the EU nor in the Member States. However, such independent institutions exist in diverse forms in several Member States and could hence be understood as a principle of democratic governance common to the Member States. Such an understanding has not yet evolved. The central theoretical problem is that regulatory theories which explain the legitimacy of independent institutions as an alternative to traditional representation remain outside the methodology of traditional democratic theory. Economic constitutional theory, based on social contract theory and widely neglected in the legal constitutional debate, offers a methodological approach to understanding independent regulatory institutions as part of representative democratic governance.