A dozen defendants are being tried on rebellion and other charges stemming from their roles in pushing ahead with a unilateral independence declaration of Catalonia in October 2017.
A sensitive trial against a dozen Catalan separatist politicians and activists got underway on Tuesday in Spain's Supreme Court amid protests by pro-independence supporters and a highly volatile political environment.
The defendants are being tried on rebellion and other charges stemming from their roles in pushing ahead with a unilateral independence declaration in October 2017. The declaration was based on the results of a divisive secession referendum that ignored a constitutional ban.
The trial, arguably Spain's most important in four decades of democracy, began as the future of Prime Minister Pedro Sanchez's minority government hinges on last-minute negotiations with Catalan pro-independence parties to back his 2019 budget.
Sanchez could be forced to call an early election if the Catalan separatists, whose support brought the Socialists to power last year, don't change their current position of voting against the prime minister's spending plan on Wednesday.
The separatists want Sanchez to agree to talks on self-determination for their region, but the government argues that the country's constitution doesn't allow it.
Opening the parliamentary debate on Tuesday, Spanish Budget Minister Maria Jesus Montero told Catalan lawmakers that the government would "not give in to any blackmail by anybody."
"Under no circumstance will we admit that the right to self-determination in Catalonia appears in any talking points," she said.
Journalist Jaime Velazquez explains what the atmosphere is like in Madrid.
A divided region
Tensions between regional and central authorities peaked with the 2017 breakaway attempt but the conflict has been festering ever since. The 7.5 million residents of Catalonia remain divided by the secession question.
On Tuesday, pro-independence protesters briefly blocked highways in the northeastern region and roads in its capital, Barcelona.
In Madrid, right-wing protesters carrying national flags shouted as lawyers and three defendants who were free on bail entered the 18th-century convent that houses Spain's Supreme Court.
Former Catalan Vice President Oriol Junqueras, the regional parliament's former speaker Carme Forcadell and the other 10 defendants weren't expected to testify on Tuesday, but they sat on four benches in the middle of the courtroom.
Holding papers in their hands and smiling at each other at times, the defendants sat facing a seven-judge panel headed by Supreme Court magistrate Manuel Marchena, who moderates the proceedings.
Junqueras' lawyer, Andreu Van Den Eynde, was the first to speak, arguing that the cause goes "against political dissidence."
"We are before an exceptional trial," he told the judges, adding that "self-determination is the formula to avoid conflicts in the world."
Catalan President Quim Torra, a fervent separatist, followed the proceedings from the back of the courtroom, where 100 seats were reserved for defendants' relatives, journalists and members of the public who lined up for hours to get one of the limited spots.
A 'stress test' for democracy
Carles Puigdemont, Torra's predecessor who fled from Spain, called for the 12 separatists to be absolved for their alleged crimes and called the trial "a stress test for the Spanish democracy."
Addressing reporters at a news conference in Berlin, the former Catalan leader added, "I trust, however, that the Spanish state will take advantage of this chance to issue the correct sentence, which is absolution."
Puigdemont said all democracies around the world should be inspired "by the Catalan struggle for democracy and the image of our civil and political leaders on trial concerns all of (those) who believe in a stronger democracy."
He also questioned why the European Union was "more concerned by that is going on in for example in Venezuela than what is happening in Madrid today."
Puigdemont successfully avoided extradition to Spain when a German court refused to send him back on charges of rebellion last year.
Those who stayed behind and showed up in court are the ones facing trial now. Puigdemont's No 2 at the time, Junqueras, faces up to 25 in prison if he's found guilty of rebellion, while others charged with sedition or misuse of public funds could get lower sentences if convicted.
The proceedings were being broadcast live on TV in a display of transparency that aims to fight the separatists' attack on the court's credibility.
Authorities in Spain have dismissed the notion that the trial is political and say it follows the Europe Union's highest standards.
Proceedings were likely to last for at least three months.
The verdicts and any sentences will be delivered months later.