Pigs are flying.

First in the United Kingdom, where Brits stunned the world when they voted in June to become to first country in history to leave the European Union. Then in the United States, where Donald Trump rose from a career in real estate and reality television to seize the White House in a November election that sent shockwaves far beyond American borders.

All eyes have now turned to France, where far-right National Front leader Marine Le Pen stands to become one of the final contenders for the presidency, a prospect previously dismissed as inconceivable.

But France’s election is still five months away. On Sunday, Italy is slated to vote in a constitutional reform referendum that could oust the country’s prime minister and set the stage for what some are already calling “Italexit.”

Prime Minister Matteo Renzi called a constitutional referendum for Dec. 4 that, if successful, would drastically reshape Italy’s political framework. His package of proposed changes is complicated and difficult to understand in its entirety, to say the least. So complicated, The Telegraph points out, that a startup company is actually offering “non-biased lessons” to understand the referendum for a fee of more than $150 per hour.

Polls from last month ― the most recent available ― showed the “no” campaign with a five-point lead. That doesn’t bode well for Renzi, who vowed to resign if the referendum is voted down.

If the “no” side wins, the party leading the charge against it ― the Five Star Movement, a populist party led by comedian-turned-politician Beppe Grillo ― could be catapulted into the government. With enough seats, it could then implement a referendum on Italy’s membership in the eurozone, which it has long demanded.

Crisis would ensue, many observers believe.

“At the moment such a euro referendum were called — actually, probably the moment Five Star formed a government — Italian bond markets would go crazy, most likely bringing about a fresh banking crisis and potentially blowing up the single currency,” Bill Emmott, co-author of a documentary on Italian economic decline, wrote in the Financial Times on Wednesday.

So, what is the referendum?

To start, a “yes” vote to reform the country’s constitution would permit a major reduction of senators in parliament ― down from 315 elected senators to just 100 appointed senators. Between the Chamber and the Senate, Italy currently has a whopping 945 parliamentary members ― more than twice as many as the U.S. House of Representatives. Italy’s population is about one-fifth of the United States’.

Renzi insists the referendum does not aim to alter democracy, but rather to streamline politics in the country, which he claims is “the worst country for bureaucracy around the world” with 63 governments in its 70-year history as a republic. He has a point. As one example, The Guardian notes, it took more than three and a half years for Italy to approve a law granting children born out of wedlock equal rights to the children of married parents.

Referendum critics, who are many, argue that the reforms would steer power away from parliament and into Renzi’s lap by stripping Italians of the right to choose their representatives.

But reforms are necessary if Italy wants to jump-start its ailing economy, which has fared on par with debt-strangled Greece in recent years.

Remo Casilli / Reuters Beppe Grillo, the founder of the anti-establishment Five Star Movement, talks during a march in support of the 'No' vote in the upcoming constitutional reform referendum in Rome, Italy, Nov. 26, 2016.

If Italy votes “no” and Renzi steps down, the Five Star Movement could call for an early election and possibly increase its chances of taking power before 2018 ― a prospect once seen as all but impossible. In that case, the party has vowed, it will call for another referendum to abandon the eurozone, where Italy boasts the third largest economy. A “no” vote could also lead to the failure of as many as eight troubled Italian banks, the Financial Times reports.

“With Trump, exactly the same thing has happened as with my Five Star Movement ... the media were taken aback and asked us where we were before,” Grillo, who’s been referred to as the “Trump of Italy,” told the pan-European news network Euronews in November.

“We became the biggest movement in Italy and journalists and philosophers continued to say that we were benefitting from people’s dissatisfaction. We’ll get into government and they’ll ask themselves how we did it,” he said. “People just need to go and vote. We’re sure to win.”

Needless to say, Renzi’s do-or-die referendum creates a complicated situation that could yield political and economic uncertainty across Europe. Should it fail, as the polls predict it will, Italy could be on a path to join its British and American comrades in installing populist, anti-establishment leadership.

As for Le Pen, while she is ultimately expected to lose in France’s 2017 elections, Trump’s surprise victory “has made possible what was presented as completely impossible,” she told CNN.

Italy’s political establishment faces far worse odds than she does.