Catalan lawmakers were voting Wednesday on a bill that will allow regional authorities to officially call an Oct. 1 referendum on a split from Spain, making concrete a years-long defiance of central authorities, who insist the referendum as illegal.
In an effort to rein in one of the country's deepest political crises in recent years, Spain's conservative government threatened to challenge the Catalan parliament's decision to allow the vote at the country's top court. The public prosecutor's office also said it was preparing a lawsuit to punish the Catalan speakers' committee for disobeying previous court orders and for abusing power.
The plenary session in Barcelona saw tensions flare when the regional parliament's top speaker, Carme Forcadell, announced that the vote on the bill will go ahead without the customary vetting of a legal committee.
The so-called "referendum bill" was included at the last minute in Wednesday's agenda. It was likely to be passed by a pro-independence majority later in the day, paving the way for plans for the ballot to be formalized.
The pro-independence coalition ruling Catalonia, where a strong Catalan identity is built around its own language and traditions, says the bill will legitimize a binding vote on breaking away from Spain based on the right to self-determination.
The Spanish government, however, considers that the referendum violates the country's constitution because only the central authorities can make such a call.
Spain's constitutional court has previously ruled that any step taken toward a referendum on secession would be illegal. Prime Minister Mariano Rajoy on Wednesday urged the court to take punitive measures against the Catalan legislative body's committee of speakers, including Forcadell.
Wednesday's parliamentary session was an "embarrassing show" and "a kick to democracy, to Catalans and to political decency," said Deputy Prime Minister Soraya Saenz de Santamaria.
Rajoy has vowed to use all legal measures at hand to ensure the vote doesn't take place and has ordered his cabinet to be ready to challenge the constitutionality of the bill if it ends up being passed.
"We are defending the rule of law in Spain and democracy in Catalonia," his deputy, Saenz de Santamaria, said in a televised press conference that was hastily convened.
The Spanish government is trying to strike a delicate balance between offsetting the secessionist defiance and staying away from more dramatic measures that would further inflame anti-Spanish sentiments, such as suspending Catalonia's autonomous powers or declaring a state of emergency that would bring the army into the mix.
The vote is also not recognized by most of the political opposition at the national level. The leaders of the Socialists and the business-friendly Ciudadanos party declared support for the conservative government in fighting the vote.
Home to 7.5 million, the prosperous Catalonia region centered on Barcelona generates a fifth of Spain's gross domestic product and enjoys ample self-government, running its own police and with considerable powers in health and education. But key areas such as taxes, foreign affairs and most infrastructures are in the hands of the Spanish government.
The pro-independence block has argued that full control would benefit Catalonia, an idea that grew in support in times of high unemployment and harsh austerity measures as a result of Spain's 2008-2013 financial crisis. The return to solid growth has weakened public backing for independence, although polls show that almost eight out of 10 Catalans want to have the right to vote.
But a referendum in defiance of Spain's rule of law, without the blessing of central authorities, has inflamed controversy. If the vote takes place and there is a victory for the "yes" side, Catalan leaders have pledged to proclaim a new republic within 48 hours, regardless of turnout.
Former Catalan leader Artur Mas said that pushing ahead with the referendum was justified because a pro-independence coalition won the 2015 regional election. "The referendum is what we have to do because we have the mandate of the peoples of Catalonia," he said.
Mas is the highest-ranking among Catalan politicians suspended from office and fined by the country's Supreme Court for organizing a non-binding vote on independence in 2014. The "yes" vote to breaking away from Spain won at the time amid a low turnout by voters.