The Lisbon Treaty is the result of a long gestation period that started out with extraordinary ambitions but was ultimately stunted by political constraints. One of the major and most visible goals of this reform has been to instil greater coherence in EU external action. In order to achieve this, the drafters of the Treaty attempted to integrate the different parts of EU external action. This effort was only partly successful. Although it allowed for improved coherence, effectiveness and continuity in EU external action, this could only occur if the EU institutions and the Member States were able to manage to garner the political will. In this Working Paper, we argue that the current text of the Treaties carries a largely untapped potential for non-negligible improvements in the exercise of Union action abroad. By revisiting the constitutional design of the Lisbon Treaty, this paper attempts to reveal this potential. It also analyses the political constraints, both in the process that led to Lisbon and in the implementation of the new text of the Treaties.