One doesn't have to look very far in the South to find violations of individual rights... if one is looking at people whose skin color happens to be black. There are several themes threaded throughout Harper Lee's novel, and the one exploring individual and institutional racism is probably the one that gets the most attention, although it is closely tied to other themes.
Tom Robinson becomes a symbol of sorts for the violation of individual rights in Lee's novel. Alabama in the 1930's, like Mississippi and other states south of the Mason-Dixon line, is dominated by Jim Crow laws and other formal and informal parameters intended to keep black people "in their place". Being a black man in Alabama and Mississippi in the years leading up to the Civil Rights Movement was a fairly dangerous existence; even more so than women, black men were held in contempt, to be feared, hated, and kept far away from innocent white Southern women. Lynchings were not unusual, and one doesn't have to go back as far as the 1930's to remember the tragedy of the young Emmett Till, a visitor from the North who was murdered in the South for supposedly speaking to or whistling at a white woman in a general store.
This, then, is the world Lee was using as a backdrop for the novel, and for Tom Robinson's plight, which was about as bad as it could get, other than the fact that he had Atticus Finch in his corner. Because he, a black man, had tried to assist Mayella Ewell, a white girl, out of kindness, he ended up accused of assault, when the lonely young lady tried to kiss him. For this, the deck was already stacked against him, for this was the ultimate crime in Southern society; Robinson's fate was sealed the moment Bob Ewell opened his mouth.
Atticus Finch did everything he could for Robinson, much to the chagrin of the local townspeople; this is where the violation of Robinson's rights becomes so painfully apparent, because when the arguments were finished, it was obvious to every person in the courtroom that Robinson was innocent, and he was found guilty anyway. One of the most heartbreaking scenes in the novel occurred when Jem Finch, who had pumped his fist and declared "We've got him" at the conclusion of arguments, realized in spite of overwhelming evidence to the contrary, that Tom Robinson was convicted. He was the only one in the courtroom who was surprised, and he was the only one in the courtroom who cried. Atticus later commented about the jury's clear disregard for the facts of the case, "They’ve done it before and they did it tonight and they’ll do it again and when they do it – it seems that only children weep.”
Atticus knew from the beginning that the result would be thus, and the fact that the jury spent any time at all in deliberations was a small victory of sorts--highlighting, again, the lack of Robinson's authentic right to a fair trial, because juries in "white accuses black" cases normally didn't see the need to deliberate for any length of time at all. The black community of Maycomb understood deeply what Atticus had done for Tom, rising as a group in deference to him as he left the courtroom, even as Reverend Sykes instructed Scout to stand, because "Your father's passin' ".