What would a Donald Trump presidency look like? As Trump nears the 1,237 delegates needed to secure the Republican nomination, Americans have begun to ponder what once seemed a farfetched possibility. The best answer might not come from our own experience of presidents and politics. Instead, the precedent may be in Italy, where a succession of governments led by Silvio Berlusconi upended policy, political discourse, and the very fabric of democracy.

In voting for Berlusconi for the first time in 1994, Italians sought to shake up a corrupt and sclerotic political system. What Italy got was Berlusconismo, a noxious new way of managing politics and public life that lives on, even with Berlusconi outside parliament for now. The Italians’ experience may be a cautionary tale.

The biographies of the two billionaires are parallel: Trump is a reality television star; Berlusconi is a media magnate who disrupted Italy’s highly regulated television industry. They share the same bombastic, insulting style, with their vitriol often targeting strong women ranging from Megyn Kelly to Angela Merkel. Each man presents himself as a political outsider despite decades of purchasing influence in the halls of power. Before America needed to be made “great again,” Berlusconi hawked a soccer chant, Forza Italia, to stress the anti-political nature of a new political movement. Trump expresses admiration for Russian President Vladimir Putin; Berlusconi was an intimate political associate.

How it happened

The dawn of Berlusconismo followed a stormy sunset of a prior era. The shine was already fading off of his nation’s political edifice at the turn of the 1990s. The Soviet collapse brought into question Italy’s post-war political system. A single catch-all party, the Christian Democrats, supported by the Socialists, had dominated for decades. The duopoly’s stated rationale for the alliance was anti-communism, but its most salient feature was corruption, and the arrangement became an anachronism after the fall of the Berlin Wall. A major scandal -- called tangentopoli, or “bribesville” -- dealt the political status quo a final, fatal blow. The old political parties did not even survive. With 35 percent of lawmakers charged with serious crimes, it was clearly time to turn a page.

It could have been a moment of hope -- the dawn of a “Second Republic” -- a sudden, clear political transition. Instead Berlusconi, who as a businessman was long a fixture of the outgoing system, filled the gap. Having fought restrictions on private ownership of mass communications to build a personal media empire, the old cruise-ship crooner was perfectly placed to sound the amplified notes of the unlikely political outsider.

The nature of American political volatility in 2016 is different, but the disaffection toward the political establishment is similar, and Trump’s political instinct in exploiting it has been equally ruthless.

Berlusconi de-institutionalized Italy’s political parties from the outside in, while Trump has waded into GOP politics to achieve the same ends from the inside out.

Berlusconi wrecked the idea of the political party as the expression of a collective will. Forza Italia, which translates roughly to "Let’s go, Italy!," was just another channel for Berlusconi to push his own personal brand. Ninety percent of its deputies in 1994 had never held parliamentary office. That inexperience translated into a lack of political energy and policy creativity. Twenty years of Italy as a joke on the international stage starts there. Twenty years of legislation tailor-crafted to Berlusconi’s business and legal interests; of spats with the Italian judiciary; of hedonistic sideshows leaving the highest office in the land impotent while the economy sputtered. And it all started with the notion, now echoed in America by Trump, that experience in office is unimportant, even detrimental, and that the party exists merely to serve the leader. Meanwhile, Italy’s corruption continued unabated, and the economy languished. Berlusconismo left untouched the negative elements of Italian political life that had ushered him into office in the first place.

It is clear that Republican regulars understand what Trump’s takeover means for the party. Trump’s policies are hard to peg down. But just as Berlusconi is about Berlusconi, so too is Trump all about Trump. Even with a victory in November, four years spent either at his service or fighting to subvert his aims will do untold damage to the viability and credibility to the GOP.

America is, of course, not Italy. Our republic is older, for starters, and our political institutions are more entrenched and designed to withstand their occasional management by fools.

Yet the very shock elicited by Trump’s emergence suggests that such a political firewall is eroding. If Republicans choose their Berlusconi, what happens then?