Spain's re-elected Socialist government is facing a rebellion from an unexpected quarter: regional governments - many of them led by fellow Socialists - clamouring for more money as the economy slows and tax receipts shrink.
When the economy was booming, José Luis Rodríguez Zapatero, prime minister, promised Catalonia and other regions a better fiscal compact to take into account new developments, such as the huge surge of immigrants who have mainly settled in the industrial powerhouses of Catalonia and Madrid.
But with the economy slowing rapidly - it grew by only 0.3 per cent in the first quarter - it is not clear how Mr Zapatero will fulfil his promises. Pedro Solbes, the veteran finance minister, has described the demands of Spain's 17 largely self-governing regions as "a sudoku that is impossible to solve".
Spain's poorer regions, including the Socialist strongholds of Extremadura and Andalusia, are vigorous defenders of the current system, which tops up taxes levied locally with large dollops of central government funds.
Catalonia, another huge repository of Socialist votes, says the system is unfair. It is a big region of 7.5m inhabitants that contributes 19 per cent to Spain's gross domestic product. But Catalonia argues it has suffered decades of neglect and underinvestment, because taxes paid in Catalonia have gone to finance the development of poorer regions.
Parts of Catalonia's infrastructure are indeed crumbling. Last summer, Barcelona suffered a week-long blackout after a pylon fell on an electricity sub-station. Then the suburban railway network collapsed as trains broke down. When that was solved, landslides hit suburban railway tracks. A severe drought then dried up the dams that supply water to Barcelona.
In spite of the change in Spain's economic fortunes, Antoni Castells, Catalonia's regional economy minister, says he will hold Mr Zapatero to his word. He expects Catalonia's new compact to be in place this August.
Mr Castells says Spain needs to "rebalance" resources between the central government and the regions, and among the regions themselves. "The system we have now takes redistribution to extremes - we have fewer resources than poorer regions such as Andalusia and Extremadura," he says.
Mr Castells' comments, and those of José Montilla, the regional president, have not gone down well with the Socialist barons of other regions.
Extremadura, Spain's poorest region, says it will not accept the new redistribution formula being proposed by Catalonia. Andalusia, for its part, wants the government to take into account the educational needs of its large infant population. Extremadura says it is its ageing population, dispersed in small villages, that needs more attention.