If you were Aunt Alexandra from To Kill a Mockingbird, how would you go about winning the Arthur Radley vs Bob Ewell case?
Since Aunt Alexandra is no lawyer, she would have to act as a character witness for Arthur Radley and as a witness against Bob Ewell for the threats which he issued against her brother Atticus Finch, thus proving motivation for his attack upon the Finch children.
As a character witness for Boo Radley, Alexandra could testify to the gentleness and solicitousness of Boo, who sewed Jem's torn pants, and she could point out how the shy and reclusive Boo left gifts for the children in the knothole of the Radley tree near the edge of their yard. In addition, Alexandra could make the case for the bravery of Boo, who conquered his fear of leaving his house in order to rescue the Finch children from physical danger and possible death.
With respect to arguments against the reprehensible character of Bob Ewell and his motivation to harm Jem and Scout, Aunt Alexandra could point to his mendacious and spiteful words--"you nigger-lovin' bastard"--and actual threat to kill Atticus, as well as his crude act of spitting tobacco in the face of her brother because of his unfounded umbrage after the trial in which Atticus proved him a liar and pointed out his ignorant and despicable character when he was on the witness stand.