For European socialists it's a potential nightmare: After losing elections in many countries, their one-time star — ex-Italian Prime Minister Matteo Renzi — may be scheming to bust up their group in the European Parliament.

While Italian voters are focused on the March 4 national election, political insiders have been gripped by intense speculation that Renzi, the leader of the Democratic Party (PD), may be planning a post-election break from the Progressive Alliance of Socialists and Democrats (S&D) group in the European Parliament to join a future centrist force led by French President Emmanuel Macron's En Marche movement.

"There’s strong concern that Renzi will follow whatever Macron does,” said one Italian Socialist MEP, speaking on condition of anonymity. “There was recently a discussion within the Socialist group and Italians faced accusations that Renzi is playing for Macron."

With 26 MEPs, the PD forms one of the biggest delegations in the Socialist group, which counts about 190 members.

"Everybody says that this is what he has in mind and there’s even the rumor that he wants to be Macron’s Spitzenkandidat" — Anonymous Italian MEP

Renzi has repeatedly denied speculation that he could defect. But on Tuesday he clarified his view of a possible role with Macron.

"I think that we need someone who rebuilds the left in Europe. I don't think I'll be the one,” he said at a press conference with foreign correspondents in Rome.

“But I believe it's important that this process is focused on the institutional work that Macron will do together with the other leaders,” he added. “I think that's crucial to consider Macron a valuable asset, not only for the European institutions, but also for Europe's politics.”

If Renzi's exit were to come true, however, it would be a tremendous body-blow to the already battered and bruised European socialists. Revived speculation of such a move has irked European social democrat leaders, who note with disdain that Macron does not yet even have a party outside of France and that he's not considered a left-winger.

But a meeting in Rome last month between Renzi and Albert Rivera, the leader of Spain's liberal-progressive Ciudadanos party, fueled rumors in the Italian press and among officials in Rome and Brussels that Renzi is considering a partnership with Macron.

In the European Parliament, Ciudadanos forms part of the centrist Alliance of Liberals and Democrats for Europe (ALDE) group.

Rivera, in interviews during his visit to Italy, said there was active consideration of jointly developing a transnational candidate list for the 2019 European Parliament election that would draw from the ranks of Ciudadanos, PD and En Marche.

At a party convention in Madrid earlier this month, Cuidadanos voted to drop references to "democratic socialism" from the party's ideological platform and to endorse "progressive liberalism" in its place.

'Macron's European spirit'

The Italian Socialist MEP said that on a few occasions, Italians in the European Parliament who are allied with Renzi had acted “more Macronist than the Macronists."

The MEP added: "Everybody says that this is what he has in mind and there’s even the rumor that he wants to be Macron’s Spitzenkandidat [the lead-candidate for president of the European Commission]."

The speculation has already spread well beyond the European Parliament. “I have heard the same thing this morning,” said one senior Eastern European diplomat last week.

Although no such move will happen before the March election, and it's unclear if all MEPs from Renzi's party would leave the Socialist group, there are already clear signs that Renzi is willing to move in this direction, said another Socialist MEP, who also spoke anonymously. The clearest such indication is that, in Italy's coming election, Renzi has put forward candidates who are “moderate socialists, former members of the PD, and people with centrist experience."

“The party which will emerge will be more centrist, with more Macron-inspired policies,” added the MEP.

For Paolo De Castro, another Socialist MEP and member of the PD, some in the Socialists & Democrats group have taken a line that is "a bit too far-left for us."

"For now, we want Macron's ideas to find a house inside the S&D," De Castro said."But if it's not possible, we will see."

"We are progressive and share Macron's European spirit," he added.

Survival strategy

While the European Parliament last week voted down proposals to adopt transnational lists for the 2019 EU election, talk of a potential Renzi defection continues to grip Brussels, where EU leaders mainly hope the Italian election yields a pro-European coalition between the PD and Silvio Berlusconi's center-right Forza Italia.

While it may seem far-fetched that Rivera travelled to Rome as Macron's emissary, the fact that it fueled speculation highlights how much influence the French president is perceived to have gained.

At the Brussels headquarters of the Party of European Socialists (the pan-EU party to which PD MEPs belong), center-left leaders said they remained confident of the PD's loyalty, and noted that the Italians had played a major role in shaping the PES resolution on the 2019 election, which reiterated the group's support for the Spitzenkandidat process and set a goal of finding new allies.

"Our political family will aim to build up a coalition of progressive and pro-European forces in the newly elected European Parliament that would vote for the PES Common Candidate to be next European Commission President," reads the PES resolution.

With opinion polls in Italy showing the PD trailing in voter intentions, one senior official in the Italian government said it would make sense for Renzi to join Macron, given his dim prospects at home.

If Renzi's party fares badly in the Italian election, it is not clear Macron will be so enthusiastic about teaming up.

"This is clearly a possible road for Renzi, if this will help him to survive after the vote," the Italian official said. "And if it will also be convenient for Macron, there’s little doubt he’ll go that way."

How convenient or appealing a Renzi alliance might be for Macron remains to be seen. The French president is being courted by all the major European political families, including the center-right European People's Party and the centrist ALDE.

If Renzi's party fares badly in the Italian elections, it is not clear Macron will be so enthusiastic about teaming up. On the other hand, if Renzi's party performs stronger than expected, perhaps he won't be so eager to leave Rome after all.

Giada Zampano contributed reporting.