On tonight's episode of Game of Thrones, Tyrion went on trial. He was accused of a crime he didn't commit — again. But in Westeros, the accused don't have very many rights, if any. The right to a fair trial, or counsel, or due process — these are foreign concepts in King's Landing, where no judge recuses himself just because he's the father of the person on trial, or the grandfather of the victim in question. Impartial judges? What are those?
Last time Tyrion faced charges (when Catelyn Stark accused him of a murder attempt on her son Bran, and then her sister Lysa Arryn accused him of the murder of her husband, a crime we learned last week that she herself committed), he demanded a trial. And when it turned out that Lysa's son would be his judge, he opted for a trial by combat. "I understand the law," Tyrion told the court then. But what is the law in Westeros?
Ultimately, the law is determined by whoever is king, or whoever he deems stand in his place, as Tommen did tonight with his grandfather Tywin. That person's word is law, and he can determine sentences at his discretion. And so far, their responses to criminal suspects were common to those in medieval times. Someone breaks an oath? Death. Someone steals or smuggles something? They get flogged, or in some instances, lose a hand or fingers (see Davos's hand). Someone commits rape? Castration. Although flaying is outlawed, the Boltons still use it as a punishment — poor Theon.
If a lord or king sentences someone to death, there are a variety of methods at their disposal — hanging, beheading, and burning being just a few. (The latter a preference of the followers of the Lord of Light, Melisandre's religion). Ned Stark believed that the man who passes the sentence should also be the one to hear someone's last words and to swing the sword — which is why our introduction to him was as a family man who brought his sons to witness his beheading a deserter of the Night's Watch. Someone who broke an oath to the Night's Watch isn't usually granted leniency, since taking the black in the first place was usually in exchange for a pardon for another crime. (Women, however, didn't have the option).
During a trial by lord, evidence must be brought forward, and witnesses must testify. Cross-examination is even allowed. The trial will often start with a prayer from a Septon asking the Father (one of the Seven) to guide them towards justice, and that Septon will make witnesses swear an oath of honesty before testifying. In earlier times, the High Septons would appoint seven judges to try a case — and if a woman is accused, three of those judges might be women.
But for this particular trial, Tyrion had three judges — Tywin, Mace Tyrell, and Oberyn Martell. This is already a better circumstance for him than his last almost-trial by lord, when Lysa Arryn's little boy was to hear the evidence and make his judgment, because he wanted to "make the bad man fly" out the Moon Door, even before evidence was heard. And while the audience might have known he was innocent this time, the "evidence" was stacked against him. All those times we've enjoyed Tyrion slapping Joffrey or giving the boy-king a much-needed dressing-down now look like motive. Which is why he requested a trial by combat, which allows the accused to sidestep any actual trial. Tyrion knows that. If he or his champion (the person he chooses to fight on his behalf, as Bronn did at the Eyrie) remain alive at the end, he is exonerated, evidence be damned. But even if he or his champion dies, and he's declared guilty, Tyrion wins a victory against Tywin — the Lannister line will die out. The only question is, who will be his champion?