Silvio Berlusconi resorted to a familiar tactic to appeal to the crowd during a recent political comeback speech on the enchanting Italian island of Ischia: a joke laced with sexual innuendo.

Addressing the topic of immigration, the 81-year-old proudly recounted the time his good friend Muammar Gaddafi took him on a tour of a migrant centre, during which Berlusconi noted the absence of bidets in the lavatories. When the late Libyan dictator asked what a bidet was used for, Berlusconi emphasised the importance of washing before oral sex. The billionaire’s punchline – “I taught the Africans about foreplay” – had its desired effect, drawing laughter and applause.

Yes, the politician some Italians call Il Cavaliere (the knight) is back, still combining his penchant for vulgarity with a honed instinct for power.

The outcome of regional elections in Sicily last Sunday confirmed his remarkable capacity for survival over a long political career tainted by sex scandals, countless allegations of corruption and a tax fraud conviction which many pundits predicted would kill him off. Berlusconi succeeded in forging a winning coalition out of his centre-right Forza Italia and the two far-right parties – the Northern League and Brothers of Italy.

In doing so, he crushed the populist Five Star Movement’s dream of governing its first region and compounded the disarray within the centre-left Democratic party, which had been in power in Sicily since 2012.

The results, seen as a barometer of how things might play out in national elections due in spring, thrust the media and property magnate back into the forefront of Italian politics, six years after he was forced to resign over claims he paid for sex with an underage prostitute and four years after he was ejected from parliament over the tax fraud conviction.

In a further reflection of his enduring vitality, the comeback comes less than 18 months after Berlusconi underwent open-heart surgery.

“Sicily has chosen the path of real, serious, constructive change, based on honesty, competence and experience,” he wrote on his Facebook page, while ascribing the success, which saw Forza Italia’s Nello Musumeci become president of Sicily, to his many appearances on the island in the run-up to the vote.

Berlusconi’s political track record is not exactly stellar, but his second term as prime minister, between 2001 and 2006, is the longest held by any Italian leader since the second world war. It’s this experience and longevity that his loyal band of supporters find so appealing.

Catia Polidori, a Forza Italia parliamentarian and deputy minister of economic development in his last government, said: “It’s no surprise that Berlusconi has returned to the centre of the political scene.

“His resignation was forced by an international plot, but his leadership was respected. He’s a great businessman and led a better economy; if you look at the economic data from the period he was in office, it was a lot better than it is now. Pensions were higher, people lived better, there was less poverty and less unemployment.”

Berlusconi currently cannot run for office, but is appealing against his tax fraud conviction. Photograph: Luca Bruno/AP

Polidori also applauded his good relations with Gaddafi, saying: “We never had the kind of migrants’ invasion that we have today.” She also brushed aside the sex scandals. “We know the real Berlusconi – he’s kind and is one of the most elegant men in the world. With regards to the women in his party, he’s always admired us and our work.”

During his time away from the central political scene, Berlusconi has nurtured a softer image, projecting himself as a lover of nature and animals, announcing last year that he had become vegetarian. On the day before the Sicily elections, he posted a photo of himself on Instagram taking a stroll around Catania’s botanical gardens. He and his 32-year-old girlfriend, Francesca Pascale, keep 10 dogs at home, while sheep wander around their well-manicured lawns.

“Berlusconi is much more moderate these days, in politics and in his personal life,” insisted Polidori.

Meanwhile, the Italian government has lurched from one unelected prime minister to the next, with the former leader, Matteo Renzi, the head of the ruling centre-left Democratic party, being forced to quit last December over his failed referendum on a constitutional overhaul.

The 42-year-old is plotting his own 2018 comeback, beginning an eight-week tour of Italy by train in October as part of his campaign. “But the truth is that, politically, Renzi is now a spent force,” said Giovanni Orsina, a political science professor at Rome’s Luiss University. “Many people see him as arrogant. He’s our Theresa May – he bet all his money on the referendum exactly the same way she bet all hers on the general election, although he fared even worse.”

The consequences of the referendum left the Democratic party in crisis, paving the way for the centre-right to re-emerge as a viable option for a long-disillusioned electorate. Even though Forza Italia hovered around 14% in an opinion poll on Thursday, behind the Five Star Movement, which leads with 27.4%, and the Democratic party, in second place with 25.6%, a recent change in electoral law allowing parties to form alliances ahead of an election could see it replicate its Sicily success nationally.

That doesn’t mean to say Berlusconi will be prime minister again: he’s currently appealing against a ban from office over the fraud conviction to the European court of human rights, but it is unlikely that a verdict will be delivered before the ballot.

Either way, there is a strong chance he could end up pulling the strings of power, as voters fed up with the left and suspicious of the Five Star Movement either switch to the right or simply refrain from voting.

“Certainly, there are reverberations with Sicily but we must remember that half of the electorate there didn’t vote – that says more about the state of Italian politics and is something we need to pay closer attention to,” said Franco Pavoncello, a political science professor and the president of Rome’s John Cabot University.

Berlusconi has been credited as an alchemist, able to form a coalition that could strike a chord with moderate voters over issues such as immigration, crime and the sluggish economy, even if they despise far-right parties.

“A leftwing voter will never like the Northern League,” said Orsina. “But a rightwing voter might say, ‘I dislike their rhetoric but I will vote for the coalition with Forza Italia as I know Berlusconi will keep them in check, because that’s what he’s been doing for years’.”

But given the choices, there are a lot of reasons for Italians to be depressed as the elections near, he added.

“To think that Berlusconi is the best that Italian politics can give is a sign of the inability of the system to rejuvenate itself, to propose new leaders,” he said. “Many people say they would never vote for him again, that he is unbearable. But there are some who will, albeit unhappily.”