Catalan separatist politicians are demanding an independence referendum in exchange for keeping Spain’s Left-wing government in power.
On Friday they blocked the conservatives from taking power, refusing to back a vote to install Alberto Núñez Feijóo, despite his party being the largest after July elections.
It leaves Spain’s Socialist prime minister, Pedro Sánchez, needing support from the Catalans to cling on to power and avoid fresh elections.
Catalonia’s two main pro-independence parties joined forces in favour of a regional parliamentary motion pledging not to support a future government of Spain unless it promises to “work towards bringing about effective conditions in which to hold a referendum”.
Friday’s agreement between the ERC and Junts (Together) Catalan parties came hours before their MPs in the Spanish national parliament voted to block the investiture as prime minister of Mr Feijóo, the leader of Spain’s conservative Popular Party (PP), for the second time in a week.
Mr Sánchez will have his turn to attempt to cobble together a majority in which half a dozen Left-wing and regional forces will be needed to support the Socialist leader.
The support of ERC and Junts is crucial to Mr Sánchez, who has been prime minister at the head of seemingly precarious minority governments since 2018.
The alternative is a repeat election in January.
Mr Sánchez and other members of his government have already indicated that they will agree to a political amnesty for Catalan politicians and activists who still face criminal charges arising from the events of 2017. The region’s parliament declared independence after a wildcat referendum marked by violent clashes between the police and voters.
But supporting preparations for a referendum in Catalonia could constitute a concession too far.
“If we have to go back to the ballot box and let the citizens choose, we will,” Salvador Illa, the leader of the Catalan Socialist Party, said on Friday.
“We will not take a single step on the path of the rupture and division of Catalan society,” added Mr Illa, who was Mr Sánchez’s health minister during the Covid pandemic.
Mr Feijóo said that he was against both the amnesty and a referendum, and challenged Mr Sánchez to clarify his position.
Mr Sánchez did not intervene in this week’s debates, which led to Mr Feijóo twice falling short of a majority with 172 votes in the 350-strong Congress.
The PP leader was supported by the far-Right Vox, something that several Catalan and Basque parties mentioned as an impediment for their support.