The former prime minister and leader of a party that won 10m votes in the last election is now a convicted criminal

SILVIO BERLUSCONI often liked to boast that although he had been put on trial any number of times (more than a dozen, in fact), Italy's supreme court had never convicted him of any crimes. Never mind that he was sometimes found guilty in lower courts—he was always acquitted on appeal or saved by statutes of limitations. Mr Berlusconi can no longer wave that ostensibly clean record before voters. On August 1st the supreme court upheld a prison sentence against him for tax fraud. The colourful former prime minister and leader of a party that won nearly 10m votes in the last election is now a convicted criminal.

The supreme court sentenced Mr Berlusconi to four years in jail, but three will be lopped off by an amnesty introduced in 2006 (ironically by his eternal rival Romano Prodi, a former centre-left prime minister). And since Italian courts seldom jail first offenders with a year or less to serve (and rarely impose community service on those over the age of 70), the 76-year-old Mr Berlusconi will most likely be put under house arrest. One day. These things take a while to arrange in Italy.

In the meantime, Italy's politicians are going to have to deal with what is perhaps the most explosive part of the ruling. The judges upheld a ban on Mr Berlusconi holding public office, but asked the appeals court in Milan to look again at how long it should last (court-watchers reckon one to three years). The decision will then have to be ratified in the Senate, where Mr Berlusconi is a member. His followers will likely try to block it.

Mr Berlusconi's People of Freedom (PdL) movement is an essential component of the current government, a left-right coalition led by Enrico Letta. The prime minister would expect his centre-left Democratic Party (PD) to help keep his government afloat by voting with its coalition partners. But how many PD lawmakers could bring themselves to defy a verdict of the courts and vote in support of a man whom many of them detest?

Tensions within the centre-left have been growing for months—between its ex-Communist and formerly Christian Democratic wings, and between supporters and opponents of the ambitious young mayor of Florence, Matteo Renzi. The PD must now decide whether to continue to share cabinet seats with a party led by a convicted tax fraudster. Within minutes of the judgement, members of Beppe Grillo's anti-establishment Five Star movement were goading the centre-leftists into withdrawing their support.

Before the supreme court announced its ruling, Mr Berlusconi said that even if he were convicted he would not bring down the government. But that does not mean that its survival is assured.

(Photo credit: AFP)