Long before the cold war and the Iron Curtain's construction, the European continent was marked by a developmental divide in which the east suffered relative economic deprivation compared to the west. This article revisits the sources of ‘economic backwardness’ in eastern Europe and asks whether post‐communist states' membership in the European Union (EU) upends the earlier structural conditions that had traditionally prevented east–west economic convergence. The article finds that while there is more economic opportunity for post‐communist states in the EU than outside it, EU membership does not subvert the major drivers of the developmental divide. EU membership does, however, limit economic volatility for the New Member States (NMS), which, in historical perspective, is a boon for eastern populations and stabilizing for democratic politics.