This essay critically examines the provisions on democratic principles within the Lisbon Treaty and their potential to address the European Union's democratic deficit. The introduction establishes the historical context of the EU's democratic legitimacy, highlighting the role of the European Parliament and the challenges posed by the democratic deficit. The analysis delves into the Treaty's amendments to the Maastricht and Rome Treaties, evaluating the legitimacy of European integration, the concept of democratic deficit, and the role of citizen participation. The essay explores the evolution of the Treaty, including the failed European Constitution and the subsequent reforms. It emphasizes the importance of competitive democracy, parliamentarization, and the increased role of European citizens and civil society organizations. The discussion covers the Treaty's impact on local and regional authorities, transparency, and the challenges of complex governance structures. The conclusion summarizes the Treaty's impact, emphasizing the importance of legal implementation, open public deliberation, and active citizen involvement to enhance the quality of democracy in the EU. The essay uses multiple sources and references to support its arguments.