The Cardassian tribunal at which Miles O'Brien, seized from a runabout while going on leave, was tried for arming the Maquis under a legal system that fixes the verdict before the hearing begins.
In the Deep Space Nine episode Tribunal, Gul Evek intercepts the runabout carrying Miles and Keiko O'Brien on holiday and arrests O'Brien. He is taken to Cardassia Prime, processed brutally and told that he has already been found guilty and sentenced to death; the trial exists only to show the public how justice works.
His appointed conservator, Kovat, intends to help him confess gracefully, while Chief Archon Makbar presides. Odo, who was once an officer of the Cardassian court, is allowed to act as O'Brien's nestor.
On the station, Sisko's staff discover that the warheads supposedly supplied to the Maquis were taken by Boone, a Cardassian agent surgically altered to pass as a human. When Sisko walks Boone into the courtroom, Makbar abruptly sets the verdict aside and frees O'Brien rather than see the plot exposed.