(Bloomberg) -- Italy’s Five Star Movement and the Democratic Party are unlikely bedfellows, and they’ll need to work hard to convince President Sergio Mattarella they can put their animosity and policy disagreements behind them and govern together.

The two parties are weighing an alliance to thwart a bid by Matteo Salvini, the leader of the anti-immigrant League party, to claim the premiership. Salvini is aiming to force new elections by ousting Prime Minister Giuseppe Conte, who addresses parliament later on Tuesday.

Conte’s appearance in parliament could lead to a confidence vote, and if he loses it would start the process of installing an alternative government or herald a new national ballot.

Alternatively, Conte could forego the vote and head directly to the Quirinale presidential palace to hand in his resignation.

Leading officials from the Democratic Party, or PD, have argued that their group should pair with Five Star, and there is a certain logic to a linkup now: polls suggest that Salvini would clean up in a snap election and both Five Star and the PD would likely be in for a long period in opposition.

Between them, Five Star and the PD have the votes to form a coalition and leave Salvini out in the cold. But that’s only if they can persuade Mattarella that they can form a stable government capable of enacting key legislation like the 2020 budget and avoiding another damaging clash with the European Union over Italy’s precarious public finances.

The head of state, who has the sole power to appoint governments or call elections, may not be easily won over. The memory of the drawn-out consultations that led to the current administration will be fresh in his mind. Five Star, the biggest party in the 2018 election, played both sides, courting first the PD, then the League.

The president will be reluctant to allow for any of the back-and-forth negotiations that kept markets nervous and the country without a government for almost three months, newspaper Corriere della Sera reported on Monday.

One thing is clear: the rocky marriage between Luigi Di Maio’s Five Star and the League is over. Salvini is “no longer a credible interlocutor,” Five Star said, and vowed to back Conte.

The prime minister, who does not belong to any political group, is due to appear before the Senate on Tuesday at 3 p.m. local time.

Depending on whether they can persuade independents to join their alliance, Five Star and the PD could command about 180 seats in the 321-seat upper house, or Senate, compared with the ruling coalition’s 165. In the lower house, the two parties could cobble together a comfortable majority of around 360 seats.

‘Recipe for Disaster’

While that looks workable on paper, some analysts are skeptical.

“The PD and Five Star have diverging agendas in too many areas, including infrastructure and fiscal policy,” said Francesco Galietti, founder and chief executive officer at Policy Sonar. “What you have is a perfect recipe for disaster. I find it difficult to believe that a PD-Five Star axis can be pieced together in the first place -- let alone survive past the fourth quarter of 2019.”

A coalition with the establishment PD would also be a humiliating climbdown for Five Star, since the two parties have traded insults and been at odds on almost every major issue for years.

For its part, the PD is hamstrung by internal divisions, with new leader Nicola Zingaretti so far unable to exert full control over the party’s lawmakers.

Most of them have ties to former Premier Matteo Renzi, who was the first to approach Five Star about forming a government. That prompted criticism from some senior PD officials, who accused Renzi of trying to weaken Zingaretti to pave the way for the creation of his own new party.

PD leaders are set to meet Wednesday to decide on the party’s position in the wake of Conte’s speech.

“If there won’t be the conditions for a strong new government than it is better to vote,” Zingaretti said Monday evening.

To contact the reporters on this story: Jerrold Colten in Milan at jcolten@bloomberg.net;Lorenzo Totaro in Rome at ltotaro@bloomberg.net

To contact the editors responsible for this story: Chad Thomas at cthomas16@bloomberg.net, Iain Rogers, Tommaso Ebhardt

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