Spain's Supreme Court considered an appeal on Thursday by Catalan separatist president Quim Torra against a conviction for disobedience that saw him disqualified from holding public office for 18 months.
If his appeal is rejected, Torra could be dismissed from office in a move that risks exacerbating a bitter dispute within Catalonia's deeply divided separatist movement and potentially trigger early regional elections.
The case centres on the use of Catalan separatist symbols on public buildings in this wealthy northeastern region, whose regional government is pushing for independence from Spain.
If the Supreme Court ratifies the sentence, which was handed down in December by Catalonia's top court, Torra would have to stand down -- but he could defy the order.
The case centres on Torra's refusal to take down a banner with separatist slogans from his government's headquarters in March 2019 as ordered by the election board on grounds it flouted institutional neutrality ahead of an April election.
Torra, who was elected in May 2018, twice ignored a deadline to remove the banner, and before finally doing so, tried to switch it for another with a similar message.
Torra has defended his conduct as freedom of expression.
He called his trial "aberrant and grotesque" as he left the hearing in Madrid and accused the Spanish state of trying to "disqualify a president in the midst of a pandemic and a monumental crisis" for "claiming fundamental rights with a peaceful banner".
The court has not said when its decision will be published.
Torra has been allowed to remain in power during the appeal process.
Should he be dismissed, it would create yet another crisis within Catalonia's deeply-divided coalition which comprises his hardline Junts per Catalunya (Together for Catalonia) and its partner the Republican Left of Catalonia (ERC).
The growing divisions between the two prompted Torra to call for early regional elections in January but they were not organised because of the coronavirus crisis.
If Torra stands down, the regional parliament would have to chose a new president. But if the independence factions failed to agree on a name, it would trigger fresh Catalan elections.
The regional turbulence could also impact on the government of Prime Minister Pedro Sanchez who was re-elected in January thanks to the tacit support of ERC in exchange for fresh dialogue on solving the Catalan separatist crisis.
The talks would aim to address the breach created through the failed independence bid of 2017 which sparked Spain's worst political crisis in decades.
