Fourth is the matter of free-riding. Uhlig (2002) focused his
discussion of free-riding and the SGP on the effects of centralized
monetary policy combined with decentralized fiscal policy. Uhlig
regards the SGP as essential in preventing free-riding in the form of
excessively high deficits. The cause for concern over debt levels
hinges on the independence of the central bank, because excessive
levels of debt might lead to a crisis in which the ECB might be
morally, although not legally, bound to bail out insolvent countries.