This formative period of EU law witnessed an intense struggle over the emergence of a constitutional practice. While the supranational institutions, including the European Commission, the European Court of Justice and the European Parliament, as well as EU law academics helped to develop and promote the constitutional practice, member state governments and judiciaries were generally reluctant to embrace it. The struggle resulted in an uneasy stalemate in which the constitutional practice was allowed to influence the doctrines, shape and functioning of the European legal order that now underpins the EU, but a majority of member state governments rejected European constitutionalism as the legitimating principle of the new EU formed on basis of the Treaty of Maastricht (1992). The struggle and eventual stalemate over the constitutional practice traced in this book accounts for the fragile and partial system of rule of law that exists in the EU today.