In Harper Lee's To Kill a Mockingbird, what passages from the trial show unfairness?
In Harper Lee's To Kill a Mockingbird, Atticus's closing speech to the jury is full of passages that speak of the unfairness of the trial.
To begin with, Atticus points out that the case should never have gone to trial because there was no, as Atticus phrases it, "corroborative evidence," meaning evidence that confirms other evidence (Ch. 20). The only evidence being used in the trial was the testimonies of witnesses whose credibility had been called into question upon cross-examination. Hence, the first thing unfair about the trial is that, as Atticus points out, "...absence of any corroborative evidence, [Tom Robinson] was indicted on a capital charge and is now on trial for his life ..." (Ch. 20).
A second unfair aspect about the trial is that, as Atticus proves, any physical evidence points to Robinson's innocence and Bob Ewell's guilt. Atticus points out in his closing remarks to the jury, "We don't know [what Mayella's father did to her], but there is circumstantial evidence to indicate that Mayella Ewell was beaten savagely by someone who led almost exclusively with this left" (Ch. 20). Atticus further points out that Robinson could not even use his crippled left hand well enough to take the oath. Hence, the trial is unfair because all evidence shows that Robinson could not possibly have committed the crime he is being accused of.