In the aftermath of the shock result of the Nice Treaty referendum in Ireland in June 20011 it was commonly stated that the result did not represent the electorate’s rejection of European Union (EU) enlargement. In fact both supporters and opponents of the Nice Treaty agreed wholeheartedly on this point. The Taoiseach (Irish Prime Minister) and his Foreign Minister assured their counterparts in the EU and the candidate states of Central and Eastern Europe (CEE) that purely domestic factors explained the result –enlargement had not been an issue. Opponents of the Treaty, similarly, couched every public statement with an insistence that they were in favour of enlargement. These claims were treated with some scepticism in the CEE candidate states. Not only would the result complicate the ongoing enlargement negotiations; it might postpone accession indefinitely. This article has one central objective: it seeks to analyse the extent to which the issue of EU enlargement really mattered in the 2001 and 2002 Nice Treaty referendum campaigns and, more generally, in the evolving European debate in Ireland. The analysis proceeds through an examination of four crucial issue areas that figured prominently in the Nice Treaty campaign of 2001 and have remained to the fore in discussion at the National Forum on Europe throughout 2002.2 On each of these issues there exist profound disagreements between Ireland’s pro-Europeans and an emerging Euro-sceptic lobby. Analysis of each individual issue is set out against the contextual arguments deployed regarding enlargement. Further, it is contended the range of concerns expressed in Ireland about enlargement, whether with respect to institutional reform or policy issues, also exist in many other EU states. Indeed, fear and unease about the implications of enlargement permeate political dicsourse across the EU. This article begins by analysing the reaction to the shock 2001 referendum result across Europe.