Italy's anti-establishment Five Star movement fired a warning shot across Prime Minister Matteo Renzi's bow Monday with a landmark victory in the first round of Rome's mayoral race.
Five Star (M5S) candidate Virginia Raggi looks likely to become the capital's first female mayor after easily taking the lead over Roberto Giachetti of Renzi's centre-left Democratic Party (PD), tapping into anger over corruption scandals in the Eternal City.
The movement also celebrated gains in other cities, mirroring the rise of populist and anti-establishment parties across Europe.
"A historic result. #Let's change everything", a jubilant M5S tweeted.
Lawyer Raggi, 37, who snapped up nearly 36 percent of the vote according to the provisional official tally, will face Giachetti, who took 24 percent, in a run-off on June 19.
Losing control of Rome would not augur well for Renzi four months before a referendum on constitutional reforms designed to end decades of gridlock in parliament.
The 41-year-old premier has vowed to resign if voters reject the reforms.
"Unless there is a startling and dramatic turn in events, the capital is going to have a 'Grillino' mayor," political commentator Stefano Folli said in the Repubblica daily, using a nickname for the movement's members.
"The optimism and hope in the future needed if voters are to back the ruling party proved too weak. This should worry the prime minister, considering the challenges of the coming months," he said.
The Italian capital has been without an elected leader since last October, when Ignazio Marino, a member of PD, was forced to quit over an expenses scandal.
The city is also still dealing with the fallout from Mafia Capitale, a scandal that erupted in 2014 when dozens of businessmen, politicians and officials were arrested on suspicion of having conspired for years to siphon off city funds through rigged tenders and other scams.
In a further blow to the PD, the 55-year-old Giachetti had to fight hard in Rome to beat Giorgia Meloni, a candidate put up by one of several small groups that emerged from Italy's neo-fascist movement.
In Turin, the party also failed to clinch an all-out victory, and will have to face off against the M5S candidate, while in Milan, the PD appeared to have won against the right only by the skin of its teeth.
"(Renzi's) party is in a terrible state, it is at risk all over the place, even in the cities it considered in the bag," commentator Marco Travaglio said in the left-wing Il Fatto Quotidiano daily.
A Five Star win in Rome would boost the populist movement -- founded in 2009 by wild-eyed and outspoken comedian Beppe Grillo -- as it seeks to cement its status as a mainstream party.
"Romans are sending a clear message. We are witnessing a historic moment," Raggi said in a nighttime victory address.
The "Grillini" will be hoping victory will give them the platform they need to transform themselves into Italy's principal opposition in the runup to national elections due by June 2018 at the latest.
But experts have warned it could be the movement's undoing, landing a politically inexperienced team with a city not only plagued with corruption, refuse and transport problems but notoriously difficult to administer.
"Winning in Rome would land them with a hot potato. I hope for their sake they do not," Piergiorgio Corbetta, research director at the Cattaneo di Bologna institute, told AFP.
Overall, more than 13 million people nationwide were asked to cast their ballots to choose members of 1,300 municipal councils in a two-round ballot.
Renzi, who played little part in most of the elections, played down their significance ahead of the vote, saying they were "about mayors, the people whose job it is to repair the streets, not the government of the country".
But on Monday he told a press conference that while Giachetti had "performed a minor miracle" by coming second in Rome after the problems with the outgoing mayor, "we are not happy".
And in Naples, where Renzi had personally rolled up his sleeves for a PD victory, the ruling party failed to make it even to the second round.
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