The Fog of War is fascinating. Robert McNamara, the Rumsfeld of his day, is remarkably honest and precise about his mistakes and successes, while just following orders. I don't believe that he didn't know about Napalm though.
A running theme is that conflicts are often caused by leaders who obsessively believe in false realities. There's a damning recording of a bloodthirsty LBJ outright reversing Kennedy's Vietnam withdrawal plan, because he was so convinced of the Domino theory.