What role should the European Parliament ofthe European Union assume in the post-Nice run-up to further enlargement? Should it continue catalysing system transformation by re-defining its obligations in the light of contemporary circumstances and needs? By exploiting existing rules and by setting out future visions, including blueprints for a constitution, MEPs are developing the EP as the custodian, conscience and guardian of the kind of liberal democratic values, norms and behaviour appropriate to the millennium and characteristic of western liberal democratic representative government. This paper looks at how this has occurred. It shows how the EP moved from being the federalising dynamo behind realising a democratic institutional balance to promoting a participatory democracy as the champion ofthe people. The paper divides into four sections: (i) examines the EP's transformation from assembly to co-legislature arguing that it perpetually seeks re- definition; (ii) relates this to a re-conceptualisation of democratic legitimacy; (iii) addresses normative issues and the linkage between the institutional and civil dimensions to democratic legitimacy; and (iv) outlines roles that might be both necessary and appropriate to a supranational legislature in the post-Nice treaty run- up to the next wave of enlargement and crucially fundamental institutional reform to accommodate new member states.