Roberto Saviano, Italy's best-known anti-Mafia author and a leading human rights campaigner, went on trial for libel on Tuesday for calling Prime Minister Giorgia Meloni a "bastard".
If convicted, he could face up to three years' imprisonment, but under Italy's legal system a fine of at least around 500 euros ($520) or a suspended sentence are more likely.
"I'll defend the legitimacy of the critique of Power, even when it is harsh," the 43-year-old told Reuters in written remarks ahead of appearing before a Rome court.
Meloni sued Saviano following a December 2020 TV interview in which he lambasted her and fellow right-wing leader Matteo Salvini over their attacks on migrant rescue NGOs.
"All the bullshit [said about NGOs], sea taxis, cruises [for migrants]," he said. "All I can say is: bastards, how could you? Meloni, Salvini: bastards."
Saviano spoke after seeing footage of a sea rescue by Spanish NGO Open Arms in which a six-month old baby from Guinea died before he could be airlifted to Italy.
Meloni, whose Brothers of Italy party was then in opposition, responded with legal action against the "serial hater" Saviano.
But her lawyer Luca Libra told reporters outside the courtroom she may consider dropping the lawsuit - as she has been urged to by the PEN International writers' association.
The trial was adjourned to Dec 12 after a short opening hearing in which Salvini asked to be admitted as a plaintiff, meaning he could also win damages if Saviano was found guilty.
The case is set to play out against the backdrop of more disputes between migrant rescue charities and Italy's new right-wing government.
Rome authorities accuse NGO ships of acting illegally, and last week refused to let one of them dock in Italy, forcing it to sail to France and provoking a spat with the French government.
Saviano, who has lived under 24-hour police protection since his 2006 breakthrough book "Gomorrah", an expose on the Naples mafia that was adapted into a movie and a TV series, was unrepentant about his attack on Meloni.
"What should I be apologising for? For doing my duty to criticise Power, as all intellectuals should do?" he said in the comments to Reuters.
The author, who often clashes with right-wing politicians, said he faced two more defamation cases pitting him against Salvini, now deputy prime minister, and Culture Minister Gennaro Sangiuliano.