AS A WRITER who has covered Silvio Berlusconi since he became Italy’s prime minister in 1994, it has been difficult not to be overcome with a powerful sense of déjà vu all over again watching the presidential campaign of Donald Trump.

Some of the resemblances are obvious as well as uncanny. Both are billionaires who made their initial fortunes in real estate, whose wealth and playboy lifestyles turned them into celebrities. Both have had ugly divorces and brag of their sexual prowess. Trump notably defended his manhood at the debate last week, while Berlusconi once said, “Life is a matter of perspective: Think of all the women in the world who want to sleep with me but don’t know it.” (This was before Berlusconi began holding “bunga bunga” parties with prostitutes.) They are masters of media manipulation, Berlusconi as Italy’s largest private television owner, Trump as the star of his own reality TV show and creator of the Trump “brand.” Entering politics, both have styled themselves as the ultimate anti-politician — as the super-successful entrepreneur running against gray “professional politicians” who have never met a payroll and are ruining their respective countries.

The strategy worked well for Berlusconi — he won three national elections and served as prime minister for nine years between 1994 and 2011. Will it do the same for Trump?

Both are deliberately transgressive, breaking through the tedium of politics-as-usual by using vulgar language, insulting and shouting down opponents, adopting simple catchy slogans, and making off-color jokes and misogynistic remarks. Their verbal “gaffes” — which would be suicide for most politicians — are actually part of their appeal. I recall when Berlusconi presided over a European summit, and when negotiations stalled, he said to the assembled heads of state, “Let’s lighten up the climate by talking about soccer and women.” He turned to Gerhard Schroder, then-chancellor of Germany, who had been married four times. “You, Gerhard,” Berlusconi said. “What can you tell us about women?” The remark was greeted with a chill. At first I thought, How could Berlusconi be so foolish? But his true audience was not the European heads of state — it was Italian men back home. After all, what are the two favorite topics in most Italian bars? Soccer and women.

Similarly, one might have thought Trump would have doomed himself with remarks apparently about the menstrual cycle of Fox News anchor Megyn Kelly, and his ability to get “a young and beautiful piece of ass.” But this nose-thumbing of “political correctness” has allowed both Berlusconi and Trump to successfully create an unusual hybrid persona: a kind of everyman’s billionaire. Someone who, on the one hand, by virtue of extreme wealth, success, and audacity, is a kind of superman for whom the normal rules of conduct don’t apply. At the same time, their plain, coarse speech connects viscerally with many people, particularly the less educated part of the electorate. They have an improbable inter-class appeal, very rich men who pursue policies that benefit the very rich (see the proposed Trump tax cut) while making effective rhetorical appeals, in a beerhall idiom, to the grievances of the struggling members of the middle and working classes.

Neither Trump nor Berlusconi has a real political program; what they are selling is themselves. Berlusconi used to say that what Italy needs is more Berlusconi. I recall a very telling moment in his first election campaign: During a TV debate, his opponent, the economist Luigi Spaventa, was pointing out the holes and inconsistencies in Berlusconi’s economic program, and Berlusconi stopped him mid-sentence and pointed to the victories of his soccer club, AC Milan: “Before trying to compete with me, try, at least, winning a couple of national championships!” The remark had the air of unassailable truth — however irrelevant it might be to Berlusconi’s fitness to govern. Similarly, when asked how he is going to get Mexico to pay for a giant wall between its country and ours, Trump simply responds, “Don’t worry, they’ll pay!”

Yet there is another element — a systemic one — that helps explain why Italy and the U.S. are the only major democracies in which a billionaire circus has raised its tent: the almost total deregulation of broadcast media. Berlusconi managed through political connections (with evidence of massive bribery) to acquire a virtual monopoly of private television in the 1970s. He introduced highly partisan news programs, giving TV shows to such on-air bullies as Vittorio Sgarbi and Paolo Liguori, who peddled conspiracy theories like Glenn Beck and shouted down political opponents in styles similar to Bill O’Reilly. In both Italy and the U.S., you have major networks that are, in essence, the media arm of one of the country’s main political parties. It’s important to realize, however, that the transformation of the media landscapes of both Italy and the U.S. did not simply happen, but were the result, in part, of political decisions.

About 30 years ago, the Federal Communications Commission had quaint rules called the Fairness Doctrine and the Equal Time Doctrine. They were seen as a way of guaranteeing that private license holders operated at least partly in the public interest and guaranteed a degree of pluralism of views. These rules made a certain amount of sense in an analog age in which the number of frequencies was limited. Television (and television news) was dominated by the big three networks, each of which competed for as much of the total market as it could get. It made no sense for any of them to create an overtly partisan newscast that would alienate Republican or Democratic viewers. This was hardly a golden age — broadcast news was arguably dull, centrist, and establishmentarian — but there were basic rules of civility and a certain respect for factual accuracy.

With the advent of cable television in the 1970s and the Reagan revolution of the 1980s, this all changed. President Reagan’s FCC chairman, Mark Fowler, insisted that television was no different than any other commercial appliance — “a toaster with pictures,” he called it. The technological changes in the field — the emergence of cable — reinforced this position. With dozens and eventually hundreds of channels, it was felt, the old rules of fairness and balance were passé, because the sheer number of channels would ensure pluralism. What this view failed to appreciate was that it didn’t correspond with the way people actually consume news: They do not watch multiple points of view, switching frequently between PBS, Fox, MSNBC, and CNN. Instead, each group seeks out the news that fits its own ideological assumptions and stays there.

In 1987, Fowler eliminated the Fairness Doctrine. The next year, Rush Limbaugh created his nationally syndicated radio program. Fox News, headed by former Republican Party operative Roger Ailes, began operating in 1996.

IN BRITAIN, Germany, and France, state media companies still dominate the airwaves and act as a kind of referee for civil discourse and establishing commonly accepted facts; the situation that prevails is akin to American TV before it was disrupted by Reagan and Fox. It has not prevented extremist political movements from developing, but it has meant that the principal conservative parties and their electorates accept basic realities such as global warming and the fact that the invasion of Iraq was not a rousing success. You cannot simply say anything on their airwaves.

Italy, however, has been the outlier in Europe. Not only were Berlusconi’s own networks transformed into his air force and artillery, he consistently placed his own people in strategic positions in the state broadcasting system — his ostensible competitor. A director of news of the largest state channel invented a system known as “the sandwich,” whereby all political news would be presented in the same manner: It would begin with the Berlusconi government’s view of the news, contain a thin slice of opposition opinion, and conclude with another thicker slice of government rebuttal. Without his elaborate web of media protection, it is hard to understand how Berlusconi could have survived so many appalling scandals.

To reinforce their alternate realities, both Berlusconi and Trump have made a special target of the so-called mainstream media. Trump’s use of social media to go after his critics is reminiscent of the frequent attacks Berlusconi made on his critics in the media. One particularly disturbing moment occurred the other day when Trump urged camera operators at one of his rallies to point their lenses at a particular protester, suddenly making her the object of public rage. It reminded me of a moment when Berlusconi stood side by side his good friend Vladimir Putin at a press conference in Moscow. When a Russian journalist asked a tough question of the Russian leader (this was several years ago when such a thing was still possible), Berlusconi made the gesture of firing a machine gun at the woman. In a country where several critical journalists have actually been murdered, this was decidedly unfunny.

Just recently, Trump indicated that he intended to change the libel laws of this country to keep people from writing bad things about him. “The press is a real problem in this country,” he said. “They’re worse than the politicians. … They can write anything they want and you cannot sue them, because the libel laws, they essentially don’t exist, and one of the things I’m going to do is I’m going to open up the libel laws.”

Berlusconi did not have quite the same problem in Italy, where libel laws are far more favorable to plaintiffs. In American libel law, truth is an absolute defense and in the case of media publishing false information about a public figure, the plaintiff must show that the speaker knew it was false or acted recklessly. In Italy’s defamation laws, something can be true and yet defamatory. Berlusconi and his close associates have sued dozens of journalists and critics over the years, often losing but costing his critics money, intimidating publishers, and keeping them tied up in the courts or reduced to silence.

I have learned about the nice distinctions of Italian defamation law from personal experience. When my book, The Sack of Rome, came out in Italy, Berlusconi’s best friend and the head of his media company, Mediaset, sued me for criminal defamation. His main argument was not that the facts in the book were incorrect, but that I should have included other exculpatory facts that would have left the reader with a more positive and, in his view, truer picture of him. Fortunately, I won the case at trial and on appeal, but in Italy, where there are three levels of justice, 11 years after initial charges were filed, the case is still working its way through the legal system.

Are there lessons from Berlusconi that might help us predict Trump’s trajectory and defend against it? Yes and no. Indro Montanelli, a conservative Italian journalist and a fierce Berlusconi critic, said that Italy would need to develop an immunity to Berlusconi by absorbing a certain dose of Berlusconi. Unfortunately, it took 17 years of constant scandals and economic incompetence for Italians to grow weary of Berlusconi. On the positive side, the American electoral season is much longer than Italy’s. Berlusconi came to power in a kind of rapid blitzkrieg of barely three months. Nine months of all Trump all the time may help create Trump fatigue and allow some immunity to develop. Moreover, Berlusconi benefited from the complications of Italy’s complex semi-proportional system: He won elections without ever winning a majority of votes; it will be harder for Trump to reach 50.1 percent.

Lastly, Berlusconi and Trump have a penchant for self-destruction. The giddiness of public adoration — the narcissistic high of constant media attention — creates a feeling of omnipotence that causes them to make mistakes, as Trump did the other day in resisting the invitation to distance himself from David Duke and the KKK. What Berlusconi did — and Trump follows the same path — is create a kind of ongoing reality show whose ratings depended on him continuing to do and say outrageous things. Berlusconi, as Trump, often overestimated himself and underestimated his opponents. Berlusconi won three times but he also lost twice to a politician (Romano Prodi) who was far duller and far more competent. We have to hope it doesn’t take 17 years for America to tire of the Donald.