Because Tom Robinson is a black man accused by a white woman whom he has touched, and because he has said that he "felt sorry for her," under the Jim Crow Laws and the prevailing attitudes of whites towards blacks, a jury of twelve white men would normally be swift in their assertion that Tom is "guilty." Atticus explains this to Jem, saying,
In our courts, when it's a white man's word against a black man's, the white man always wins. They're ugly, but those are the fact of life."
Further, he explains to Jem that people carry their resentments with them, even into a jury box. But, because the jury took a few hours to reach a verdict, Atticus is encouraged. He explains that there was one man on that jury who "took considerable wearing down" because he was originally "rarin' for an outright acquittal." As Jem presses him, Atticus suggests that the juror was one of the Old Sarum bunch. Although Mr. Cunningham was not present, his kinsman was. Atticus explains that although they were a problem at the jailhouse when he guarded Tom,
...once you earned their respect, they were for you tooth and nail.
and Atticus feels that they left with respect for the Finches. So, the kinsman (a "double first cousin") of Mr. Cunningham fought for an acquittal of Tom. If one man can object in this way, perhaps more will object another time and justice will truly be served.
Chapter 23: The jury diliberated and handed out their judgement at a longer time than usual. Normally, cases like these would come and go in a flash. However Tom Robinson's case had garnerd more support and sympahty. One of the Cunninghams ( who was a member of the jury) fought passionately for the aquittal of Tom Robinson.