Kingsolver's main intention in invoking the Bataan Death March is to account for Nathan's extreme personality, though, presumably, a personality would have to be somewhat extreme to begin with to respond to these events as Nathan does. However, the interweaving of the Bataan Death March into the Price family's saga has further effects than simply making Nathan more believable. The presence of this tragedy in the story serves to heighten the already considerable sense of injustice and brutality that hangs over the narrative, deepening and widening our collective guilt to include more events and more segments of the world population. Until this point, it has only been Western powers that have been shown as responsible for brutality, oppression, and inhuman acts, but here we see an Eastern power partaking in this legacy of cruelty as well. The "heart of darkness" born of greed and arrogance is not limited to the West, but can and does infect all parts of humanity. It is, we might surmise, hearkening back to Nathan's symbolic garden, the real original sin of human beings.
Turning back to the exploration of Nathan's history and development, Orleanna's latest narrative not only sheds light on her husband's general religious fervor, but more specifically on his treatment of his family. In particular, it comes to seem likely that Nathan's most recent actions are not simply the result of a staggering neglect towards his wife and daughters, but that, at least in part, they are motivated by an active desire to abuse and hurt these women.
Nathan believes that God is constantly watching him, and that he must never deviate from the path that God has set out for him. He includes sexual lust among the deviations that he is to avoid, and yet he cannot help but succumb to his desires periodically. Nathan is enraged by his own sexual urges. Instead of turning his rage on himself, however, he conveniently turns his rage on his beautiful wife for tempting him, and on his daughters for being the physical manifestations of his lapses in will power. In a sense, it seems, he hates these women, resenting them for reminding him that he is not what he wants to believe himself. An active hatred would help explain not only his present endangerment of their lives, but also the constant pattern of physical and emotional abuse, as well as the complete and utter lack of tenderness.
Leah is hit harder than anyone, because all her values are changing. Can read whole book as mainly about Leah's coming of age—loss of one kind of faith and replacement by another. "It's still frightening when things you love appear suddenly changed from what you have always known." "If his decision to keep us here wasn't right, then what else might he be wrong about? It has opened up in my heart a sickening world of doubts and possibilities, where before I had only faith in my father and love for the Lord. Without that rock of certainty underfoot, the Congo is a fearsome place to have to sink or swim."