Berlusconi finally falls. Could he take Italy's government with him?

The ex-premier's sentence for tax evasion - one of many in the past two decades - was upheld Thursday, putting Italy's ruling coalition at risk.

Italians are accustomed to seeing their three-time former Prime Minister Silvio Berlusconi in the courtroom: The most recent trial over tax fraud was one of some two dozen in 20 years.

But when they woke up today, for the first time in history, Italians found he had been handed a sentence – four years in prison – that he cannot appeal.

It is symbolically dramatic for Mr. Berlusconi, who today called the decision unjust, but in reality it has more implications for the stability of Italy's coalition government.

Berlusconi's first definitive sentence – his other trials, spanning sex with an underage prostitute to wiretapping, have been appealed or dropped after statues of limitation expired – is a setback for the media tycoon, who until now had never been held accountable for crimes alleged against him. But it doesn’t mean he’s out of politics.

First of all, he will serve only one of the four years handed down because of efforts to reduce prison overcrowding, as Alberto Nardellli, the co-founder of electionista, a service that monitors politics globally, writes at CNN. Nor will the world see dramatic photos of Berlusconi behind bars: Because he is over 70, he’ll either serve his sentence at home or do community service. 

In addition to the sentencing, he faces a ban on public office, which the higher court ruled that a lower court must review. It’s unclear what will be decided, and whether he’ll have to step down from office now – he is a serving senator – or after the parliamentary term ends. But Berlusconi could still shape the politics of Italy, which he's done for 20 years, from the sidelines and step back in after the ban lapses. 

For Italy, the news is certainly a symbolic victory for those who have watched Berlusconi emerge unscathed from one scandal after another. Today, the BBC ran a statement from anti-establishment politician Beppe Grillo. He compared the sentence to the fall of the Berlin Wall, the BBC reports, saying Berlusconi "polluted, corrupted and paralyzed Italian politics for 21 years.” 

But if some feel that justice has finally been served, the sentencing could put political stability at risk. The Italian Senate will have to take up the matter now, also voting on Berlusconi’s ineligibility to hold public office and when it would take place.  And it promises to be an ugly fight, threatening the fragile left-right coalition formed by Enrico Letta. Markets sighed with relief when Mr. Letta stepped into the position of prime minister, after February elections led to a political standoff between the right and left.

Letta urged "a climate of serenity" for the good of the country, the BBC writes, while Italian President Giorgio Napolitano also called for calm. "The country needs to rediscover serenity and cohesion on vitally important institutional matters which have for too long seen it divided and unable to enact reforms," he said.

“We're in uncharted territory, and what happens next politically is nearly impossible to predict,” writes Mr. Nardellli. “But the possible outcomes include the downfall of the government.”