What do Scout's thrashings of Walter Cunningham and Francis foreshadow in To Kill a Mockingbird?

Scout thrashes Walter and Francis to foreshadow the trouble that her family will have during the trial and the outcome of the trial.

Scout is young, and like many young people she sometimes has trouble handing her temper.  This often results in her getting into fights when she does not like what people say about her.  The problem Scout has is that her father is defending a black man, and most people in Maycomb are racist and do not approve.

Scout’s conflict with Walter Cunningham is evidence of the fact that people in Maycomb are against Atticus defending his client.  Atticus was appointed to defend Tom Robinson for the rape allegation, but he would have done it anyway, even though most of the rest of Maycomb has convicted Robinson in the court of public opinion.

Atticus tells Scout to avoid fighting and be the bigger person, but she says that she soon forgot.

Cecil Jacobs made me forget. He had announced in the schoolyard the day before that Scout Finch’s daddy defended niggers. I denied it, but told Jem.

“What’d he mean sayin‘ that?” I asked. (Ch. 9)

Cecil’s reaction is the same as the reaction of most of the town.  It demonstrates that even children in Maycomb believed that the trial was a foregone conclusion.  Scout had no idea what Cecil Jacobs was talking about, but she fought him anyway to defend her family’s honor.

Scout even has trouble with her own family.  She learns that Aunt Alexandra also does not approve of Atticus’s actions, and Frances's comments about her father also cause Scout to get into a fight.

“If Uncle Atticus lets you run around with stray dogs, that’s his own business, like Grandma says, so it ain’t your fault. I guess it ain’t your fault if Uncle Atticus is a nigger-lover besides, but I’m here to tell you it certainly does mortify the rest of the family—” (Ch. 9)

Certain family members believe that Atticus is hurting the family name just by defending a black man.  Atticus does not care what they think, because he believes in giving the case everything he has regardless of how futile the outcome.  He tells Scout there is no way he can win, but that doesn’t mean he won’t try.

The trial, and Atticus’s loss of the case, is foreshadowed by these fights.  It is through these altercations that Scout has that we learn how the people of Maycomb feel about African Americans and Tom Robinson’s case.  He is a black man accused of raping a white woman, and as far as they are concerned just being accused makes him guilty.