The leader of the Partido Popular, Alberto Núñez-Feijóo. | Tarek


MPs will on Tuesday begin debating Alberto Nunez-Feijoo's bid to become Spain's next prime minister a day before an inauguration vote the right-wing opposition leader is almost certain to lose.

Without the necessary support to obtain 176 votes in the 350-seat parliament, Feijoo is likely to use the opportunity to attack Pedro Sanchez's efforts to stay on as premier by courting a hardline Catalan separatist party cast in the role of kingmaker.

A month after Spain's inconclusive July election, King Felipe VI tasked Feijoo -- whose Partido Popular (PP) won the most votes -- with forming a new government ahead of an investiture vote on September 27.

Although he has garnered the support of the far-right Vox plus a handful of other seats, Feijoo has found himself four seats short -- with regional parties rejecting any alliance that would include Vox over its hardline opposition to Spain's system of devolved regional politics.

"If I accepted" the demands of regional parties, "I could be prime minister next week. But I don't intend to give in to blackmail," Feijoo told El Mundo daily today, acknowledging he faced almost certain defeat in Wednesday's vote.

"I will not rule at any price."

The debate could allow Feijoo "to outline an alternative programme that would be a big contrast" from what Sanchez is proposing for the future, Astrid Barrio, a political scientist at Valencia University, said.

In this context, the 62-year-old has spent the last few weeks attacking Sanchez for the likely concessions he will need to make to the hardline Catalan separatist JxCat party to stay in power.

That was the central theme of the Sunday mass protest he called in Madrid, under the mantra: "Defending the equality of all Spaniards".

Carrying Spanish flags and banners, around 40,000 people, according to the organisers and the Madrid authorities, gathered two days before the debate on Feijoo, who currently does not have a majority, becoming head of government.

JxCat's main demand for its seven key votes in support of Sanchez is for an amnesty for hundreds of activists facing legal action over the 2017 failed Catalan separatist bid which sparked Spain's worst political crisis in decades.

An amnesty "has no place within the Constitution", Feijoo said Thursday, describing it on X, formerly Twitter, as "an unjustified and unethical attack on the rule of law and the separation of powers" because it defies rulings handed down by the courts.

The parliamentary debate begins on Tuesday with a speech by Feijoo followed by a first vote on Wednesday when he will need to secure 176 votes in favour.

If he fails, he will then face a second vote on Friday when he will need a simple majority of more votes in favour than against.

Barring any unexpected surprises, Feijoo is not expected to pass either vote which will give Sanchez a turn to try to piece together a government.

If Sanchez is unable to pass an investiture vote withing two months of Wednesday's vote, Spain will face new elections, most likely in January.

To pass the vote, Sanchez is banking on support from two Catalan separatist parties which both supported his candidate for parliamentary speaker in a vote last month.

For that, they had demanded that lawmakers be permitted to speak in Catalan, Basque and Galician when addressing Spain's parliament -- which came into force last Tuesday.

But approving an amnesty, which would affect Catalan separatist leaders who fled Spain to avoid prosecution over the independence bid like JxCat leader Carles Puigdemont -- is an extremely sensitive political issue.

Approving an amnesty is not only a red line for the right but also for elements within Sanchez's own Socialist party.

Among the Socialists opposed to the move are Castilla La Mancha's regional leader and former premier Felipe Gonzalez, who on Wednesday said: "We must not let ourselves be blackmailed."

Although Sanchez's government in 2021 pardoned around a dozen Catalan separatists who had been jailed over the failed secession bid, he has yet to speak publicly about the amnesty issue.

"I will be faithful to the policy of normalisation in Catalonia," he said on the sidelines of the UN General Assembly in New York, referring to his efforts to calm separatist tensions in the wealthy northeastern region since taking office five years ago.