What is the theme in All My Sons by Arthur Miller?

Keller's suicide at the end of All My Sons is both an act of atonement and a desperate cry for forgiveness. Joe cannot reconcile his comfortable present with the sins of his pass. He seeks forgiveness. Unfortunately forgiveness means atoning for his role in the faulty airplane parts. He must confess his knowledge as well as sending an innocent man to prison. Jo cannot find forgiveness unless he faces his own jail time and his own demons.