One of the salient features of fiscal federalism in OECD countries during the past decade has been a trend toward decentralisation, as policy reforms have increased the power of state and local governments. From 1995 to 2008 the average share of sub-central in general government spending rose from less than 31% to more than 33%, while the share of sub-central in general government tax revenues rose from 16% to 17%. Some countries have embarked on a long-term decentralisation path involving wide-ranging changes to their institutional arrangements (). However, many attempts to reform fiscal relations have encountered difficulties. Various reforms – including the territorial reorganisation of public service delivery, changes to the sub-central tax structure and the tightening of sub-central fiscal rules – have stalled or been introduced only partially and after several unsuccessful attempts. The technical and political obstacles to wide-ranging reforms of fiscal arrangements are formidable. The question arises as to how they may be overcome and the benefits of decentralised policy making fully realised, especially in a context where sub-central governments will have to share in the efforts of fiscal consolidation.