ROME -- Italians began voting yesterday in a two-day referendum that could herald the biggest constitutional shake-up in half a century unless Prime Minister Romano Prodi persuades the country to reject it.
Prodi, whose office would be strengthened by the overhaul, said the package would crumble national unity, weaken the presidency, and cost the nation more than $315 billion to implement.
Former prime minister Silvio Berlusconi, whose center-right coalition championed the overhaul before being ousted from power in April elections, said it would regenerate Italy's antiquated system of government.
Italy's constitution was drawn up after World War II with the aim of preventing the return of a dictator such as Benito Mussolini. But critics say it contains so many checks and balances that it has been hard to govern, with many postwar administrations surviving barely a year.
The referendum gives Berlusconi a sorely needed chance to reassert himself as leader of the center-right House of Freedoms coalition after he lost the national elections and then failed to win key seats in local polls last month.
``The House of Freedoms wants a respite from repeated defeat with a document that destroys the constitution," Prodi said in the run-up to the vote, urging Italians to vote no.
``It's an insult to our country and a distortion of the rules that govern Italy."
Both sides have predicted victory, but commentators say uncertainty over the turnout makes it impossible to predict.
The referendum would give Italy's 20 regions full autonomy over health, schooling, and policing, a move critics say would mean better services for richer northern regions, to the detriment of the poorer south.
This was a priority for the small, autonomy-minded Northern League party, a raucous member of Berlusconi's coalition that had repeatedly threatened to quit without the overhaul.
It would also give the prime minister more clout, enabling that post to hire and fire ministers and dissolve Parliament.
This should effectively halt the common Italian practice by which parties switch sides midterm and bring down a prime minister.
The referendum is needed because the measure passed by only a simple majority in Parliament in November, when Berlusconi was still prime minister, instead of the two-thirds' majority that would have made the changes automatic.