How does Jem show a loss of innocence in the book To Kill A Mockingbird when Atticus loses the Tom Robinson case?
After the guilty verdict is brought in on Tom Robinson, Jem realizes that the judicial system in which he has always believed is greatly flawed because the unified bias of eleven white men and another dissenting man who acquiesces to them is able to override justice.
Early in the narrative of To Kill a Mockingbird, Jem begins to lose his innocence when the gossip about Atticus's having taken on the role of defender for Tom Robinson is expressed in expletives and invectives, some of which are said by respected neighbors of the community. Jem is further alerted to the visceral feelings of many regarding the trial when even his own aunt remarks upon the case and, especially, when the angry lynch mob demands that Atticus turn over Tom to them.
Nevertheless, despite the disturbing emotions that Jem experiences, he is not completely disillusioned until a guilty verdict is returned on Robinson at the end of his trial. He can't reconcile the outcome with the facts of the trial, the logic of the evidence, and the undeniable truth of Tom's physical condition.
At the courthouse while the jury is out deliberating the verdict, a smiling and confident Jem remarks to pastor Sykes:
"...don't fret, we've won it....Don't see how any jury could convict on what we heard." (Ch.21)
However, the wise and experienced Reverend Sykes cautions Jem to not be so confident:
"I ain't ever seen any jury decide in favor of a colored men over a white man...." (Ch. 21)
Reverend Sykes's words are the "inconvenient truth" of which the innocent Jem has been ignorant. After the trial is over, his disappointment in mankind is great and his naïveté and innocence lost. Jem protests against the verdict--"It ain't right"-- but his faith in the judicial system has been greatly diminished and his innocence lost.
At the beginning of Chapter 21, Jem is excited because he thinks that Atticus has won the Tom Robinson case. In Jem's mind, the lack of hard evidence to support Tom raped Mayella, conflicting testimonies from the Ewells, Tom Robinson's handicap, and Bob Ewell's alcoholic tendencies are enough to acquit Tom Robinson. What Jem does not understand is the deep-rooted prejudice that the jury members feel toward African Americans. Atticus speaks about an unwritten code in Maycomb County and exposes the systemic racism during his closing argument. At the end of Chapter 21, Judge Taylor reads the verdict..." guilty." Scout explains the each "guilty" was like a stab in between Jem's shoulders. Jem displays his loss of innocence by crying and repeating the phrase, "it ain't right." (Lee 287) Atticus tells Jem that the older he gets, the more he will witness white men cheating black men. Jem becomes skeptical of his neighboring community members and can't seem to understand why they go out of their way to despise each other. Jem tells Scout that he used to think that there was only one type of person in the world, but after the trial, he's not so sure. Jem's loss of innocence is illuminated by experiencing the duality of human nature. People can be both moral and immoral, good and evil.