Absolutely. It is well developed on many fronts...not just the black/white issue.
Scout is a victim of prejudice when she proves how well she can read on the first day of school. Her teacher feels threatened by this and insists that she only read at school...not at home with her family.
Boo Radley is a victim of prejudice simply because no one has seen him in such a very long time. All sorts of ideas and stories swarm the countryside about him, but no one knows anything for sure. So, he is the victim of innuendo, childish pranks, and illogical behavior from others.
The Ewells are victims of prejudice and are often referred to as "white trash" in the novel. They are poor, they live near the black community, they have no mother, and Mayella is thought to be her own father's mistress. None of these things are approved of in the town, and so therefore this family is victimized.
Mr. Raymond is considered the town drunk and has a black mistress and children. The children discover during Tom's trial that Mr. Raymond is not drunk...in fact, his bagged bottle contains only Coca-Cola...but he is the victim of prejudice anyway. The reader is not certain which is the cause of his low position in society--his "drunkenness" or his association with his black mistress and the children he has as a result.
Of course, there are many examples of prejudice between blacks and whites in this novel as well. The theme is absolute.
It most certainly is.
The Robinson trial is, of course, a clear example. Note that while Jem comes to realize that several key members of Maycomb aided Tom (Atticus, Judge Taylor, Link Deas, the Cunningham on the jury), but the majority of the town did not. In fact, as Atticus tells his brother during their Christmas visit, that many members of the community think he should do as little as possible to help Tom. As the trial is about to take place, Scout overhears several men talking outside the courthouse about how they are distressed that Atticus really means to defend Tom. She also realizes that her teacher is prejudice, for she laments what is happening in Nazi German regarding the Jews but she was racist toward the blacks in her own town. Also, Heck Tate is willing to protect Boo at the conclusion of the novel because he is white, yet he didn't exactly go out of his way to protect Tom when Mayella and Bob Ewell accused him of rape when it was clearly not the case.
Another example of prejudice is evident in Aunt Alexandra who is prejudice against certain people based on their income and family histories. Note how horrified she is after the verdict when Scout tells her that she is going to befriend Walter Cunningham jr. Alexandra reminds her that Scout is a Finch and, as such, she is not to associate with white trash.
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