A politician with as outrageous a style as Silvio Berlusconi is bound to pick up some humiliations along the way. Being convicted of having sex with an underage prostitute was one. Having his final appeal against a conviction for tax fraud rejected was another. And some readers may remember the distinct lack of sympathy he received when his nose was broken by a protester with a statuette back in 2009.

But perhaps nothing in Berlusconi’s career has been quite as humiliating as today (Wednesday), when he was obliged to rise in the Italian Senate and advocate a vote of confidence in the government that he had just tried to destroy.

The government of Enrico Letta duly won the vote by a more than convincing margin of 235 to 70. But that’s not how it looked last weekend, when Berlusconi instructed the ministers from his party to resign their places and bring down the government. His ostensible reason was his opposition to a rise in Italy’s GST, but everyone knew that the real reason was the government’s failure to prevent a vote to expel him from the Senate as a consequence of his tax fraud conviction.

Letta, whose government started inauspiciously, handled the crisis well. He refused to accept the resignations and instead called for an immediate vote of confidence, realising – or at least gambling – that Berlusconi would not be able to carry his party with him. (The lower house is no problem for Letta because the electoral system gave his centre-left group an automatic majority; the Senate has always been the difficult part.)

That’s when the trouble started for Berlusconi. His party has never been a proper political party but fundamentally just a vehicle for his ambitions. Yet this week his associates, previously known for their loyalty, started to show they had minds of their own. Most importantly, deputy leader and party secretary Angelino Alfano broke ranks with him and advocated support for the Letta government.

It became clear that there would be enough numbers from the centre-right for the government to survive. At that point, Berlusconi had to decide which would be less humiliating: to lead the backdown himself, or to have his lack of control over his colleagues definitively and publicly demonstrated.

He chose the former, telling the Senate that “Italy needs a government that can produce structural and institutional reforms. We have decided, not without internal strife, to back the confidence vote.”

It’s a good result for Italy. Still mired in economic troubles, with the balance of power held by unrealistic populists, Letta’s grand coalition is the best of the available options. A centre-right that has emancipated itself from Berlusconi’s influence will be a more secure prop, not to mention a harbinger of a more workable party system for the future.

But for Berlusconi, it really does look like the end of the road. As long as his troubles could be portrayed as external, politically-motivated attacks, he could retain the loyalty of his own party and treasure hopes (often realised) of a comeback. An internal revolt on this week’s scale is much harder to dismiss.

I’m conscious of the fact that I (and others) have said things very like this before. Almost three years ago, I drew attention to the importance of the defection of (another) trusted lieutenant, and said “it’s hard to avoid the conclusion that Berlusconi’s career is drawing towards a close.”

Yet having just turned 77, facing expulsion and house arrest, surely this time his bag of tricks is just about empty.