He challenges the death penalty, attempting to demonstrate the hypocrisy and inhumanity of this law.
Perry Smith, though a murderer, becomes a sympathetic character in Part 2 of In Cold Blood. He was abused and abandoned as a child and rejected as an adult. Unlike Hickock, it is obvious that Smith has a conscience, because he is troubled by the acts he has committed. The fact that he cannot put the crimes out of his mind and that he cannot believe they will get away with the murders are the signs of his guilty feelings. Capote thus portrays a damaged person who never had a chance in life. Yes, he is a murderer. Yes, he should pay for his crimes, but it is hard not to feel sorry for him all the same. Capote's closely documented account of the Clutter killings asks whether a man alone can be killed for his actions when his situation has ruthlessly mistreated him. Capote's chilling description of the executions adds to his argument against the death penalty. He places the reader right there in the room with its noose and its menacing hangman. Capote describes it in all its grim detail, forcing the reader to look at the callousness of these deaths as he puts a human face on capital punishment. .
By portraying Smith so sympathetically, Capote adds ammunition to his case against capital punishment. He strengthens his argument with his presentation of psychiatric evidence. Hanging such a man, Capote suggests, is no less savage and cruel than the murders that were committed. By portraying Perry Smith as a helpless soul, we notice ourselves hoping he will not die. Capote is playing on our morals and proving that this murderer is still a person and worthy of a chance. We, however, are plagued by indecisiveness. By law, this man should be killed for his wrongdoing and justice be served, nevertheless we feel ourselves dreading his demise.
In Cold Blood demonstrated the fine line between law and morality by the way of the insanity plea.