Joe Keller wants Ann to forgive her father, Steve, who has been imprisoned for distributing cracked engine heads in the war that resulted in the death of twenty-one pilots. Steve has since been imprisoned, and Ann has cut off contact with him, ashamed of her father's actions. She explains her actions to the Kellers, saying,

It's wrong to pity a man like that. Father or no father, there's only one way to look at him.

This seems to upset Joe greatly. He tries to convince Annie that though her father made a mistake, he's not a bad man or a murderer. He repeats the phrase "a father is a father," emphasizing that the family connection should override any mistakes he might have made. He wants Ann to treat her father with kindness, to welcome him back when he is released from jail. He even asks Ann to offer Steve a spot at Joe's factory when he's out.

However, he wants this from Ann not for Steve's sake but for his own. Joe knows that he is the one who is really responsible for the shipment of the cracked engines, and he pleads for pity for Steve because he feels guilty for condemning him. He also wants to believe that if his family knew the truth about what he had done, they would not abandon him the way Ann has abandoned Steve. Joe has valued family over everything else, and he hopes his family would, too.

MOTHER. There's something bigger than the family to [Chris].

KELLER. Nothin' is bigger!

MOTHER. There is to him.

KELLER. There's nothing he could do that I wouldn't forgive. Because he's my son. Because I'm his father and he's my son.

MOTHER. Joe, I tell you...

KELLER. Nothin's bigger than that. And you're going to tell him, you understand? I'm his father and he's my son, and if there's something bigger than that I'll put a bullet in my head.

When Joe asks Ann for forgiveness for Steve, he is really asking for forgiveness for himself on behalf of his own children. But he does not get what he asked for. When his guilt is revealed, Ann reveals that Larry was so ashamed of his father that he intentionally crashed his own plane, killing himself.