ROME - Seventeen years after he first entered politics, the rocky, controversial and polarizing career of Italian Prime Minister Silvio Berlusconi could come to an end as early as Friday.

Italy's Prime Minister Silvio Berlusconi attends a debate at the Parliament in Rome October 13, 2011. [Photo/Agencies]

Berlusconi, in the latest drastic attempt to save his beleaguered government, called for a confidence vote in the lower house of the Italian parliament.

If the votes against him are greater than those on his side, Berlusconi's government is constitutionally obligated to resign. The vote could come as soon as Friday.

The 75-year-old media tycoon and political leader appeared in parliament Thursday in a last-ditch attempt to rally support to his side, saying "there are no other alternatives" and he predicted the country's economy could slide into "catastrophy" without him at the country's helm.

But the prime minister's plea literally fell on deaf ears, as all but six opposition lawmakers had walked out of the chamber in protest of his refusal to step down despite all the controversy swirling around him and his government.

For months, Berlusconi has been embroiled in legal and political difficulties ranging from the defection of key political allies, falling approval levels, an anemic economy, and three open court cases alleging, among other things, tax evasion, bribery, cronyism, influence peddling, and even paying an underage girl for sex. But he has so far managed to hold onto power - mostly, analysts say, because of the absence of a viable figure to take his place.

"Almost every argument in support of Berlusconi includes the point that there's nobody else to take his place," Roma Tre University political scientist Armando Alivera said.

And it's probably true. For all the problems Berlusconi has, the opposition is no better off. And Berlusconi never allowed any rivals to develop much of a power base within his own coalition.

Umberto Bossi, head of the separatist Northern League and the most important junior partner left in Berlusconi's coalition, vowed Thursday that Berlusconi's government would still be standing when the confidence vote concluded.

"When the vote is counted, the government will still be here," Bossi promised, saying he was in communication with his deputies to make sure they would not break ranks and put the vote in jeopardy.

But despite Bossi's efforts, defections are still taking place. Already this week, Santo Versace, the brother of design icons Donatella and the late Gianni Versace, announced he would not support Berlusconi in a confidence vote.

"The economic situation is critical," said Versace, who was elected as part of Berlusconi's coalition in 2008. "I will be voting against the government because it is better to change in the current context."

It will not take many defections or abstentions to put the prime minister's fate in doubt: at the latest head count, Berlusconi's majority in the 630-member chamber is just five, and by the time the vote takes place it could be smaller.

For him to survive, those voting in support of Berlusconi must outnumber those against him. Only the votes actually cast will count: any deputy to abstain or who does not show up to vote will not count for either side. With his razor thin majority, Berlusconi's fate could boil down to a small handful of deputies failing to be in the chamber when the votes are counted.