ROME – Silvio Berlusconi’s conviction for tax fraud, upheld late Thursday by Italy’s top court, set up a Senate showdown over his potential expulsion from parliament.

The upper house’s committee for immunities is required to vote on whether to strip Berlusconi, a three-time premier and now a senator, of his seat. The debate, which may take weeks or months, threatens to stoke divisions in the ruling coalition, weakening Prime Minister Enrico Letta’s government.

“I am absolutely aware of the politically delicate moment,” Letta said Friday at a conference in Rome. “I hope that the collective interests prevail for the good of the country, the good of Italy, and not the partisan interests.”

The fight over Berlusconi’s fate moves to the political arena after the court, which confirmed his guilty verdict, left the sentence for his crime unresolved. Berlusconi was spared the immediate enforcement of a five-year ban on holding public office because the court said it required further judicial review. Berlusconi’s four-year jail sentence is unlikely to land him in prison due to leniency guidelines.

“This legal matter could have significant political repercussions given that it is ultimately up to the Senate to vote on whether or not Berlusconi should be ineligible,” Wolfango Piccoli, an analyst with Teneo Intelligence, wrote Friday in a research report.

The Senate committee is required to consider the case because of a law passed in December under former Prime Minister Mario Monti.

The committee will hold a preliminary vote prior to a final vote in the full Senate, which could be a secret ballot, the head of the committee, Dario Stefano, told Ansa Thursday.

The divide is deepening within the ruling coalition between lawmakers loyal to Berlusconi, 76, and those who, like Letta, have traditionally opposed him. Renato Brunetta, chief whip of Berlusconi’s People of Liberty party in the lower house, said the ruling put democracy in Italy in question and vowed to rally around the ex-premier. Giuseppe Civati, a lawmaker with Letta’s Democratic Party, said it was time to plan “an exit strategy” from the alliance with Berlusconi.

Thursday’s ruling was “completely groundless” and “irresponsible,” Berlusconi said in a video message. His party will “stay in the field” and seek a majority from Italians, the former premier said.