The European Union stands out as one of the regions of the world that has most explicitly and deliberately attempted to reduce regional disparities within its membership. How effective this effort has been is a matter of open debate. The current enlargement of the European Union (EU) to less affluent new members gives rise to a fresh set of questions: How can the cohesion objective best be advanced in a context where initial income disparities will now be greater? Will the accession process cause the income of the poorer regions to converge towards EU standards or, to the contrary, will...