There already are constitutional documents  We already have such constitutional documents – the Treaty of Rome, the Maastricht Treaty and most importantly the Lisbon treaty from very recently (2009). The powers of, and relationships between the different institutional actors are clearly defined in the existing treaties. Just because the EU has expanded to incorporate new member states does not mean it needs a constitution. The Treaty of Nice was meant to have made the necessary amendments to facilitate enlargement. If it has failed, then we can simply amend the existing treaties again.