On 13 December 2007, the Member States of the European Union sign the Treaty of Lisbon, meaning that the ratification process can begin. This article, published by the European Policy Institutes Network (EPIN) in September 2008, offers a general overview of the difficulties in ratifying the treaty encountered across the European Union and presents a detailed analysis of the situation, particularly the national debate that took place in four countries: Ireland, Germany, the Czech Republic and Poland.