The Conference on the Future of Europe is an opportunity to reflect on the Union's democratic foundations, including the legislative role of the Council of the European Union (EU) and its relations with the European Parliament. Is it pertinent to reform the Council, either by reinforcing its parliamentary features or by transforming it into a Senate or a Second Chamber? Would such a change enhance the democratic legitimacy of the EU decision-making process? To answer these questions, this study looksat three connected issues in detail. First, it analyses the role of second chambers in the integration process of sovereign states in broader political entities (higher polity). Second, it examines the different bicameral systems (composition, powers, and functions), particularly in the EU Member States, but also in other models that may help as a reference. Third, it explores proposals to reform the Council put forward by leading political and academic figures. The study aims at providinga set of tools that may serve as inspiration should calls to transform this key EU institution be followed,and suggests three reform scenarios, using the instruments found inexisting parliamentary and federal systems