Mr Prodi won the vote at the cost of a damaging rift with his hard left allies. Facing the stiffest political challenge in 11 months in office, he staved off an immediate government crisis when the centre-right opposition Freedom Alliance said it would vote with his centre-left coalition on a joint motion to deploy the force. But it exacted a high price for voting with the government, forcing Mr Prodi into a humiliating admission that he was not able to muster a majority of his own on the policy after key ally Communist Refoundation said it would vote "no".
Addressing the lower Chamber of Deputies, Mr Prodi said he would ask President Oscar Luigi Scalfaro to decide his fate if his key allies in the Communist Refoundation failed to back him in the vote to deploy an Italian-led security force in the troubled Balkan state.
Refoundation, without which the centre-left government cannot muster a majority in the lower house, confirmed that it would vote against the 6,000-strong force of up to eight nations, the first of its kind to be led by Italy.
The party's stance compelled Mr Prodi to rely instead on the main centre- right opposition Freedom Alliance to support the mission.
"I declare now that if the dissent expressed by the Communist Refoundation group persists, I will go immediately to the head of state to inform him officially of the situation and await his evaluation," Mr Prodi said. The options open to President Scalfaro, the supreme arbiter in Italy's politics, include asking Mr Prodi to tender his resignation or, which is more likely, sending him to parliament for a vote of confidence, in order to determine whether his 11-month-old government stands or falls.
The split has highlighted the vulnerability of Mr Prodi's coalition to Refoundation's casting votes on a difficult domestic agenda. These include a drive to reduce Italy's social spending to prepare the country for entry into Europe's planned single currency.
Refoundation says it will back Mr Prodi in any confidence vote as long as it is not on Albania. But the coalition party leaders now want a thorough review of the stormy alliance in order to assess whether the hard left can be brought into line on key economic policies.
"What we have to do now is seek a confidence vote on the government's programme. The vote must be on precise issues and not general matters," said the Italian Foreign Minister, Lamberto Dini, leader of the centrist Italian Renewal party.
The opposition supports the idea of sending a force to Albania. But it exacted a high price for voting with the government, insisting Mr Prodi acknowledge that his parliamentary majority has been cut to shreds on the issue.