Italian Prime Minister Paolo Gentiloni votes on March 4 in Rome. (Andreas Solaro/AFP/Getty Images)

Italian populists of all leanings took a hammer to their country’s old political order in Sunday elections, crushing traditional centrist parties in favor of a kaleidoscope of alternatives on the left and right and upending their former system, according to preliminary results.

The vote plunged Europe’s fourth-largest economy into an uncertainty unique even to a nation known for cycling through leaders at a rapid clip. The shattering of the political landscape ruled out most plausible alliances among parties. But voters did not offer a clear direction for the future as they struggle with a stagnating economy and an influx of migrants, even as more than half voted for anti-establishment parties.

The surging outsider Five Star Movement captured more voters than any other party, about 32 percent, according to projections based on initial vote counts, meaning it is likely to play a key role in any governing coalition. In an extraordinary result, it appeared to have won nearly as many votes as the mainstream center-left and center-right parties combined. Italy’s complicated electoral system could lead to initial results shifting slightly, but politicians of all stripes were treating the first projections as an earthquake. 

The election drew the attention of anti-establishment crusaders from around the world, who saw the roiling populist energy of the campaign as a harbinger for other European nations. President Trump’s former strategist Stephen K. Bannon was among the people who traveled to Rome to see the final days of the campaign. Formerly fringe ideas, such as deporting 600,000 migrants who have come to Italy without proper papers in recent years, have entered the mainstream.

Now Italian leaders will have to search for a way to piece together a ruling coalition out of the squabbling factions inside the parliament, with the Five Star Movement likely playing a central role. The effort could take weeks or months. If it proves impossible, the country would have to hold fresh elections, but there is little reason to expect voters would vote differently than they did Sunday.

“Everybody will have to come talk to us,” said a triumphant Alessandro Di Battista, a senior leader of the Five Star Movement, which was founded by a comedian in 2009. He said they would seek “transparency, fairness and credibility” as they tried to build a coalition.

The election captured some of the angry energy that has swirled elsewhere in Europe and the United States. French voters last year rejected traditional parties in the first round of their presidential elections, then elected Emmanuel Macron, a self-described “radical centrist,” over his far-right opponent. In Germany, the rise of the far-right Alternative for Germany in September elections sapped strength from centrist leaders and forced the country into political paralysis that finally ended Sunday with a coalition agreement between the battered old-line parties.

But the Italian election appeared to push the atomization of political forces one step further. The Five Star Movement has never held national leadership positions and has shunned alliances in the past, making any new coalition with the party uncertain. In theory, it could partner with populist forces on the far right that share some of its skepticism of the European Union and sympathy about economic protectionism, but the parties split sharply on attitudes toward Islam and migration. That type of populist alliance would be a nightmare scenario for the European Union and probably would spark a crisis in Italian financial markets.

“We are in a transition and we don’t know where it will lead,” said Giovanni Orsina, the deputy director of the School of Government at LUISS-Guido Carli University in Rome. “The cards are being distributed for the reshuffle of the political system.”

Many voters said they were unenthusiastic about the campaign, which has been marked by clashes between far-right and anti-fascist forces and was punctuated by a shooting rampage last month in the central Italian city of Macerata that targeted African migrants. The man who confessed was a failed candidate in local elections last year for the far-right Northern League, which on Sunday showed it was shedding its regional roots by expanding into the southern Italian regions it once derided. It has now renamed itself simply the League. 

Its leader, Matteo Salvini, overhauled and rebranded the party on a nationalist platform that promised more for Italians at the expense of migrants. The message connected with voters, as the League appeared to capture more votes than its main coalition partner, former prime minister Silvio Berlusconi’s Forward Italy party, setting off another political earthquake. That result meant that even if the center-right bloc found enough lawmakers to scrape together a government, the man at the top would be Salvini, who has warned that Islam is taking over Italy and said he would make life miserable for those who came to the country without papers.

“Today is just the beginning of a revolution of common sense,” said Lorenzo Fontana, federal deputy secretary of the League. “Citizens have fully understood that the powers that be wanted to make slaves out of them.”

The anti-establishment energy captured the attention of Bannon, who has appeared sympathetic to Salvini’s nationalist message in the past. The former Trump strategist told local journalists ahead of the vote that he thought Italy was at the vanguard of a worldwide populist revolution.

Voters’ broad disillusionment stemmed from a feeling that Italy’s political establishment has failed its citizens. Living standards are where they were in 1999 even as Italy’s neighbors have improved significantly. The unemployment rate for youth is stuck at 35 percent, and the country’s most ambitious citizens are moving away. And more than 620,000 migrants have arrived in Italy since 2013, mostly from sub-Saharan Africa, putting extra pressure on a nation that scarcely felt able to take care of its own.

“I’ve lost all trust in the Italian political class, which keeps promising and promising and promising,” said Lorena Bernardini, 42, a shop owner who was voting in the ethnically mixed Esquilino neighborhood of Rome. She said she voted for the Five Star Movement because “maybe they’re not as enmeshed in the system.”

On Sunday, concerns about migration spread across the political spectrum, touching even those who said they were deeply sympathetic to refugees fleeing war and violence. One voter said that he was worried that Italy could not manage the sheer numbers.

“Here we have the benefit of the best efforts, and still we are collapsing under the pressure,” said Filippo D’Ascola, 45, who added that he voted for the center-left Democratic Party. He said he worried that many migrants were coming in search of jobs, not because they needed refuge from war. “Italy is like a billboard in Africa,” he said.

Stefano Pitrelli contributed to this report.