The issue of equal treatment under the law and the issues of physical, ideological and legal segregation are each dealt with in this novel and are each part of the 1960s civil rights movement.
The trial of Tom Robinson is a clear example of social injustice resulting from racial policy and politics as they exist both in the public mind and in the workings of the legal system. Robinson is wrongfully convicted and sentenced to death.
During his testimony, he relates that he felt sorry for the girl. This remark affronts the white men in the jury, who see it as evidence that he is overreaching his social station. Although he is clearly proven innocent, the all-white jury convicts him of rape, a crime punishable by death.
This injustice is discussed as being culturally embedded in the society of Maycomb and surprises no one when it is carried out, with the exception of children.
The civil rights movement recognized this type of injustice as being widespread under Jim Crow law, acknowledging and publicizing unfair treatment and unequal protection under the U.S. Constitution, which Jim Crow laws precipitated.
Myriad other prejudicial and discriminatory practices were committed as well, from routine denial of the right to a fair trial to outright murder...
In Harper Lee's novel, the children make waves by attending an African American church and later sitting in the African American section of the courthouse. Innocently, the children cross a social/cultural line (as defined by certain elements of Maycomb), offering further examples of the town's policies of segregation and expressing in the narrative an antipathy for these policies.
The civil rights movement worked to overturn and remove policies of segregation, institutional inequality, and unfair treatment of minorities.
Tom Robinson is treated unfairly because he is black. In the court house the blacks and whites sit in different areas