The anti-establishment Podemos party gave Spain a final hope of avoiding snap elections this week when it said it would ask supporters in a referendum if it should join other parties in supporting a coalition after all.
Podemos has so far balked at endorsing a proposed deal between the mainstream Socialist Party and the liberal Ciudadanos.
Pablo Iglesias and other party leaders said they would advice far-left voters against accepting the coalition agreement, making a reversal unlikely.
But unless Podemos budges, it is difficult to imagine a scenario in which Spaniards do not return to the polls four months after electing a new parliament.
The election in December left neither the Socialists nor the outgoing People’s Party of Mariano Rajoy with a majority.
The two have alternated in power since democracy was restored in Spain.
Although Rajoy’s conservatives came in first, the other parties refuse to give him another term as prime minister.
Socialist Party leader Pedro Sánchez proposed a coalition of the left, but it cannot govern without at least the informal support of Podemos.
The anti-establishment movement, however, insists on being properly part of a government and would rather not sit in it with the Ciudadanos, who are its ideological opposites.
It is because of Podemos‘ far-left policy proposals, which include the nationalization of major industries and a restructuring of Spain’s debt, that many Socialists are wary of collaborating too closely with it.
Polls suggest the People’s Party, some of whose members are currently under investigation for corruption, would lose votes to the Ciudadanos if there were new elections while the Socialists and Podemos could roughly retain the support they have now.
But that could change if leftwingers blame one or the other for the failure to form a government.
The internal referendum Podemos has called could be a way to deflect such blame away from the party leadership, which may find that it has overplayed its hand.
Whichever party or parties end up running Spain will have a bigger challenge on their hands than they assumed in December.
Rajoy’s caretaker administration reported last week that the 2015 deficit had come in at nearly 5.2 percent of gross domestic product, a full percentage point higher than expected. To meet the 2016 target of 2.8 percent, Madrid would have to cut another €25 billion in spending.
The Socialists and Podemos both campaigned on relaxing austerity measures, something that could lock them in a standoff with the European Commission which has to approve the budgets of all eurozone nations.