MADRID — Spain is bracing for the nation’s most sensitive trial in four decades of democracy this week, with a dozen Catalan separatists facing charges including rebellion over a failed secession bid in 2017.
The proceedings, which begin Tuesday, will be broadcast live on television and eyes will be focused on the impartiality of the Spanish Supreme Court.
Catalonia’s separatists have attacked the court’s credibility in the run-up to the trial, saying it is a puppet of the Spanish government and any ruling will be a political one that has been decided in advance.
‘‘In reality, it’s democracy itself that will go on trial,’’ Oriol Junqueras, one of the accused, wrote from jail in reply to questions sent by the Associated Press. ‘‘We are before a trial which, through a partial investigation full of falsities and irregularities, criminalizes a political option and an ideology.’’
But Supreme Court president Carlos Lesmes dismissed that notion, saying the trial is the most important since Spain’s transition to democracy in 1977 after the death of dictator General Francisco Franco.
‘‘This is a trial following the highest standards set by the European Union,’’ Lesmes recently told a group of journalists.
Lesmes said the outcome of the trial will reverberate beyond the political crisis in Catalonia.
‘‘I certainly believe that there is a huge campaign to discredit the Spanish judiciary, which forms part of a defense strategy,’’ he said.
Spanish authorities say that the separatists are guaranteed a fair trial by the very democracy founded on the rule of law that they allegedly violated.
Lesmes rejected the idea that Spanish courts operate at the whim of the government, pointing to recent guilty verdicts for prominent members of the political and economic elite, including last year’s graft conviction of former members of former prime minister Mariano Rajoy’s then-ruling party and the imprisonment, also on graft, of the king’s brother-in-law.
Junqueras, the former vice president of the Catalan regional government, and 11 others are being tried for their roles in holding an independence referendum on Oct. 1, 2017, after ignoring a ban by the country’s Constitutional Court, and for the subsequent declaration of independence 26 days later despite warnings from authorities.