How does Harper Lee introduce the Tom Robinson case so that the reader knows it will be the major conflict throughout the novel?

In the novel To Kill a Mockingbird, Harper Lee first introduces the Tom Robinson case at the beginning of Chapter 9. The chapter begins with Scout yelling at Cecil Jacobs to take back a racially charged comment directed at her father. According to Scout, Cecil Jacobs had announced to the school yard that "Scout Finch's daddy defends niggers" (Lee 99). Scout maintains self-control by not fighting Cecil Jacobs, and asks Jem what Cecil meant. Jem tells Scout to ask Atticus, and she asks Atticus later that evening if he "defends niggers." Atticus tells Scout not to use that word and says that he does defend Negroes. Scout mentions that Cecil made it sound like it was a terrible thing to defend Negroes, and Atticus begins to explain who he is defending. Atticus tells Scout that he is defending Tom Robinson. Tom is a black man who attends Calpurnia's church and is respected throughout Cal's community. He lets Scout know that it is a "peculiar case" and there is some "high talk" around town about how Atticus shouldn't take the case. Atticus goes on to say that he wouldn't be able to hold his head up in town or represent the county in the legislature if he chose not to take this case. He tells Scout, "...every lawyer gets at least one case in his lifetime that affects him personally. This one's mine, I guess" (Lee 101).

In addition to Atticus' comments about his personal convictions and duty to defend Tom Robinson, Harper Lee also illuminates the negative attention Atticus and his family are beginning to receive from Maycomb's community. Harper Lee is suggesting to the reader that the trial will become a major conflict throughout the novel.